Single electron transistors (SETs) made from single wall carbon nanotubes (SWCNTs) are promising for quantum electronic devices operating with ultra-low power consumption and allow fundamental studies of electron transport. We report on SETs made by registered in-plane growth utilizing tailored nanoscale catalyst patterns and chemical vapor deposition. Metallic SWCNTs have been removed by an electrical burn-in technique and the common gate hysteresis was removed using PMMA and baking, leading to field effect transistors with large on/off ratios up to 10^5. Further segmentation into 200 nm short semiconducting SWCNT devices created quantum dots which display conductance oscillations in the Coulomb blockade regime. The demonstrated utilization of registered in-plane growth opens possibilities to create novel SET device geometries which are more complex, i.e. laterally ordered and scalable, as required for advanced quantum electronic devices.
Transconductance as a Probe of Valley Thermodynamics in Multilayer WSe$_2$
Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS)（物质·材料纳米结构研究センター（MANA），国立物質研究所（NIMS））；Department of Nanotechnology for Sustainable Energy, Kwansei Gakuin University（关西学院大学持続可能エネルギーナノテクノロジー学科）
We present an analytical device model for a graphene bilayer field-effect transistor (GBL-FET) with a graphene bilayer as a channel, and with back and top gates. The model accounts for the dependences of the electron and hole Fermi energies as well as energy gap in different sections of the channel on the bias back-gate and top-gate voltages. Using this model, we calculate the dc and ac source-drain currents and the transconductance of GBL-FETs with both ballistic and collision dominated electron transport as functions of structural parameters, the bias back-gate and top-gate voltages, and the…
We demonstrate a graphene-MoS2 architecture integrating multiple field-effect transistors and we independently probe and correlate the conducting properties of van der Waals coupled graphene-MoS2 contacts with the ones of the MoS2 channels. Devices are fabricated starting from high-quality single-crystal monolayers grown by chemical vapor deposition and characterized by scanning Raman and photoluminescence spectroscopies. Transconductance curves of MoS2 are compared with the current-voltage characteristics of graphene contact stripes, revealing a significant suppression of transport on the n-s…
The high-frequency transconductance and current noise of top-gated single carbon nanotube transistors have been measured and used to investigate hot electron effects in one-dimensional transistors. Results are in good agreement with a theory of 1-dimensional nano-transistor. In particular the prediction of a large transconductance correction to the Johnson-Nyquist thermal noise formula is confirmed experimentally. Experiment shows that nanotube transistors can be used as fast charge detectors for quantum coherent electronics with a resolution of $13\mathrm{μe/\sqrt{Hz}}$ in the 0.2-$0.8 \mathr…
We develop an analytical device model for graphene bilayer field-effect transistors (GBL-FETs) with the back and top gates. The model is based on the Boltzmann equation for the electron transport and the Poisson equation in the weak nonlocality approximation for the potential in the GBL-FET channel. The potential distributions in the GBL-FET channel are found analytically. The source-drain current in GBL-FETs and their transconductance are expressed in terms of the geometrical parameters and applied voltages by analytical formulas in the most important limiting cases. These formulas explicitly…
Single-walled carbon nanotubes (SWNTs) have been grown via chemical vapor deposition on high-kappa dielectric SrTiO3/Si substrates, and high-performance semiconducting SWNT field-effect transistors have been fabricated using the thin SrTiO3 as gate dielectric and Si as gate electrode. The transconductance per channel width is 8900 S/m. The high transconductance cannot be explained by the increased gate capacitance; it is proposed that the increased electric field at the nanotube-electrode interface due to the high-kappa SrTiO3 decreases or eliminates the nanotube-electrode Schottky barrier.
Low-dimensional metallic transport is at the heart of modern high-performance transistors. While the best devices are currently based on III-V heterojunction quantum-well channels, we demonstrate that much greater performance gains reside in the unique properties of one-dimensional carbon nanotubes. Using recent experimental data, we show how the specific features of degenerate carrier kinetics in metallic nanotubes enable a novel class of quantum-confined signal detector whose current gain exceeds present transistor technology. We analyze the key interplay of degeneracy and scattering dynamic…
Transport measurements normally provide a macroscopic, averaged view of the sample, so that disorder prevents the observation of fragile interaction induced states. Here, we demonstrate that transconductance fluctuations in a graphene field effect transistor reflect charge localization phenomena on the nanometer scale due to the formation of a dot network which forms near incompressible quantum states. These fluctuations give access to fragile broken-symmetry and fractional quantum Hall states even though these states remain hidden in conventional magnetotransport quantities.
We incorporate an Al-AlO_x-Al single-electron transistor as the gate of a narrow (~100 nm) metal-oxide-semiconductor field-effect transistor (MOSFET). Near the MOSFET channel conductance threshold, we observe oscillations in the conductance associated with Coulomb blockade in the channel, revealing the formation of a Si single-electron transistor. Abrupt steps present in sweeps of the Al transistor conductance versus gate voltage are correlated with single-electron charging events in the Si transistor, and vice versa. Analysis of these correlations using a simple electrostatic model demonstrat…
We report finite-bias characteristics of electrical transport through phosphorus donors in silicon nanoscale transistors, in which we observe inelastic-cotunneling current in the Coulomb blockade region. The cotunneling current appears like a resonant-tunneling current peak emerging from the excited state at the crossover between blockade and non-blockade regions. These cotunneling features are unique, since the inelastic-cotunneling currents have so far been reported either as a broader hump or as a continuous increment of current. This finding is ascribed purely due to excitation-related ine…
High frequency performance limits of graphene field-effect transistors (FETs) down to a channel length of 20nm are examined by using self-consistent quantum simulations. The results indicate that although Klein band-to-band tunneling is significant for sub-100nm graphene FET, it is possible to achieve a good transconductance and ballistic on-off ratio larger than 3 even at a channel length of 20nm. At a channel length of 20nm, the intrinsic cut-off frequency remains at a couple of THz for various gate insulator thickness values, but a thin gate insulator is necessary for a good transconductanc…
Current-driven vibrational non-equilibrium induces vibrational sidebands in single-molecule transistors which arise from tunneling processes accompanied by absorption of vibrational quanta. Unlike conventional sidebands, these absorption sidebands occur in a regime where the current is nominally Coulomb blockaded. Here, we develop a detailed and analytical theory of absorption sidebands, including current-voltage characteristics as well as shot noise. We discuss the relation of our predictions to recent experiments.
We investigate vibron-assisted electron transport in single-molecule transistors containing an individual Fe4 Single-Molecule Magnet. We observe a strong suppression of the tunneling current at low bias in combination with vibron-assisted excitations. The observed features are explained by a strong electron-vibron coupling in the framework of the Franck-Condon model supported by density-functional theory.
This work reports the design and analysis of an n-type tunneling field effect transistor based on InN. The tunneling current is evaluated from the fundamental principles of quantum mechanical tunneling and semiclassical carrier transport. We investigate the RF performance of the device. High transconductance of 2 mS/um and current gain cut-off frequency of around 460 GHz makes the device suitable for THz applications. A significant reduction in gate to drain capacitance is observed under relatively higher drain bias. In this regard, the avalanche breakdown phenomenon in highly doped InN juncti…
We demonstrate a tunable negative differential resistance controlled by spin blockade in single electron transistors. The single electron transistors containing a few electrons and spin polarized source and drain contacts were formed in GaAs/GaAlAs heterojunctions using metallic gates. Coulomb blockade measurements performed as a function of applied source-drain bias, electron number and magnetic field reveal well defined regimes where a decrease in the current is observed with increasing bias. We establish that the origin of the negative differential regime is the spin-polarized detection of …
A tunable directional coupler based on Coulomb Blockade effect is presented. Two electron waveguides are coupled by a quantum dot to an injector waveguide. Electron confinement is obtained by surface Schottky gates on single GaAs/AlGaAs heterojunction. Magneto-electrical measurements down to 350 mK are presented and large transconductance oscillations are reported on both outputs up to 4.2 K. Experimental results are interpreted in terms of Coulomb Blockade effect and the relevance of the present design strategy for the implementation of an electronic multiplexer is underlined.
Single-electron transistors embedded in a suspended nanobeam or carbon nanotube may exhibit effects originating from the coupling of the electronic degrees of freedom to the mechanical oscillations of the suspended structure. Here, we investigate theoretically the consequences of a capacitive electromechanical interaction when the supporting beam is brought close to the Euler buckling instability by a lateral compressive strain. Our central result is that the low-bias current blockade, originating from the electromechanical coupling for the classical resonator, is strongly enhanced near the Eu…
We have fabricated and measured superconducting single-electron transistors with Al leads and Nb islands. At bias voltages below the gap of Nb we observe clear signatures of resonant tunneling of Cooper pairs, and of Coulomb blockade of the subgap currents due to linewidth broadening of the energy levels in the superconducting density of states of Nb. The experimental results are in good agreement with numerical simulations.
We have measured the Cooper Pair Transistor (CPT) in a tunable electromagnetic environment consisting of four one-dimensional SQUID arrays. The transport properties of the CPT in the high impedance limit, Z_env>>R_Q=6.45~kΩ, are studied for different ratios of the Josephson coupling energy to the charging energy. As the impedance of the environment is increased, the current-voltage characteristic (IVC) of the CPT develops a Coulomb blockade of Cooper pair tunneling and the measured IVCs agree qualitatively with a theory based on quasicharge dynamics for a CPT. Increasing the impedance of the e…
High-frequency performance of graphene field-effect transistors (GFETs) with boron-nitride gate dielectrics is investigated. Devices show saturating IV characteristics and fmax values as high as 34 GHz at 600-nm channel length. Bias dependence of fT and fmax and the effect of the ambipolar channel on transconductance and output resistance are also examined.
We investigate a silicon single-electron transistor (SET) in a metal-oxide-semiconductor (MOS) structure by applying a magnetic field perpendicular to the sample surface. The quantum dot is defined electrostatically in a point contact channel and by the potential barriers from negatively charged interface traps. The magnetic field dependence of the excitation spectrum is primarily driven by the Zeeman effect. In the two-electron singlet-triplet (ST) transition, electron-electron Coulomb interaction plays a significant role. The evolution of Coulomb blockade peaks with magnetic field B is also …
We have fabricated quantum dot single electron transistors, based on AlGaAs/GaAs heterojunctions without modulation doping, which exhibit clear and stable Coulomb blockade oscillations. The temperature dependence of the Coulomb blockade peak lineshape is well described by standard Coulomb blockade theory in the quantum regime. Bias spectroscopy measurements have allowed us to directly extract the charging energy, and showed clear evidence of excited state transport, confirming that individual quantum states in the dot can be resolved.
Graphene field-effect transistors are fabricated utilizing single-crystal hexagonal boron nitride (h-BN), an insulating isomorph of graphene, as the gate dielectric. The devices exhibit mobility values exceeding 10,000 cm2/V-sec and current saturation down to 500 nm channel lengths with intrinsic transconductance values above 400 mS/mm. The work demonstrates the favorable properties of using h-BN as a gate dielectric for graphene FETs.
We obtain the output characteristics of graphene field-effect transistors by using the charge-control model for the current, based on the solution of the Boltzmann equation in the field-dependent relaxation time approximation. Closed expressions for the conductance, transconductance and saturation voltage are derived. We found good agreement with the experimental data of Meric et al. [1], without assuming a carrier density-dependent velocity saturation.
Using 2-D self-consistent ballistic quantum transport simulations, we investigate the short-channel behavior of graphene field-effect transistors and its impact on the device transconductance and subsequently the intrinsic cut-off frequency (fT). Although with thin oxides, fT expectedly scales inversely with the gate length, significant band-to-band tunneling at OFF state leads to a departure from this trend in case of thick oxides. We also examine the effect of achieving better electrostatics at the cost of increased gate capacitance and illustrate that this can indeed degrade the fT. These c…
As a possible physical realization of a quantum information processor, a system with stacked self-assembled InAs quantum dots buried in GaAs in adjacent to the channel of a spin field-effect transistor has been proposed. In this system, only one of the stacked qubits, i.e. the edge qubit (the qubit closest to the channel), is measurable via "spin-blockade measurement." It is shown that the state tomography of the whole chain of the qubits is still possible even under such a restricted accessibility. The idea is to make use of the entangling dynamics of the qubits. A recipe for the two-qubit sy…
We obtain the output and transfer characteristics of graphene field-effect transistors by using the charge-control model for the current, based on the solution of the Boltzmann equation in the field-dependent relaxation time approximation. Closed expressions for the conductance, transconductance and saturation voltage are derived. We found good agreement with the experimental data of Meric et al. [Nature Nanotechnology 3, 684 (2008)] without assuming carrier density-dependent velocity saturation.
We propose an analytical device model for a graphene nanoribbon field-effect transistor (GNR-FET). The GNR-FET under consideration is based on a heterostructure which consists of an array of nanoribbons clad between the highly conducting substrate (the back gate) and the top gate controlling the dc and ac source-drain currents. Using the model developed, we derive explicit analytical formulas for the GNR-FET transconductance as a function of the signal frequency, collision frequency of electrons, and the top gate length. The transition from the ballistic and to strongly collisional electron tr…
We present a new mechanism for a spin blockade effect associated with a change in the type of magnetic anisotropy over oxidation state in a single molecule transistor, by taking an example of an individual Eu$_{2}$(C$_{8}$H$_{8}$)$_{3}$ molecule weakly coupled to non-magnetic electrodes without linker groups. The molecule switches its magnetization direction from in-plane to out-of-plane when it is charged. In other words, the magnetic anisotropy of the molecule changes from easy plane to easy axis when the molecule is charged. By solving the master equation based on model Hamiltonian, we find…
Influence of forced mechanical vibrations of a suspended single-electron transistor on electron tunneling through the quantum dot limited by the Coulomb blockade is investigated. It is shown that mechanical oscillations of the quantum dot lead to the Coulomb blockade breakdown, shown in sharp resonant peaks in the transistor conductance dependence on the excitation frequency at values corresponding to the mechanical oscillations eigen modes. Physical mechanism of the observed effect is considered. It is presumably connected with oscillations of the mutual electrical capacitances between the qu…
We have investigated shot noise in a 6-nm-diameter, semiconducting multiwalled carbon nanotube FET at 4.2 K over the frequency range 600 - 950 MHz. We find a transconductance of 3 - 3.5 $μ$S for optimal positive and negative source-drain voltages V. For the gate referred input voltage noise, we obtain 0.2 and 0.3 $μ{V}/ \sqrt{Hz}$ for V>0 and V<0, respectively. As effective charge noise this corresponds to $2-3 \cdot 10^{-5}$ e/$\sqrt{Hz}$.
The magnetopolaronic generalization of a Majorana-resonant-level (MRL) model is considered for a single-level vibrating quantum dot coupled to two half-infinite $g=1/2$ Tomonaga-Luttinger liquid (TLL) leads. A qualitatively new non-trivial formula for the effective transmission coefficient and differential conductance for resonant magnetopolaron-assisted tunneling is obtained under the assumption about a fermion-boson factorization of corresponding averages. This approach is valid for the case of weak magnetopolaronic coupling in a system. Surprisingly, it is found that despite a supposed weak…
We present a theory of a single-electron transistor exchange-coupled to a localized spin. We show how to gain detailed quantitative knowledge about the attached spin such as spin size, exchange coupling strength, Landé g-factor, and spin decay time $T_1$ by utilizing a robust blockade phenomenon of DC magnetotransport with accompanying noise enhancement. Our studies are of particular relevance to spin-resolved scanning single-electron transistor microscopy, electronic transport through nanomagnets, and the effect of hyperfine interaction on transport electrons by surrounding nuclear spins.
A nanoscale variable resistor consisting of a metal nanowire (active element), a dielectric, and a gate, is proposed. By means of the gate voltage, stochastic transitions between different conducting states of the nanowire can be induced, with a switching time as fast as picoseconds. With an appropriate choice of dielectric, the transconductance of the device, which may also be considered an ``electromechanical transistor,'' is shown to significantly exceed the conductance quantum G_0=2e^2/h, a remarkable figure of merit for a nanoscale device.
We have fabricated and measured ballistic graphene transistors with two oblique gates that can be independently biased. The gate lengths are about 38 nm and are separated by a distance of 30 nm, the tilting angle being of 45o with respect to source and drain electrodes distanced at 190 nm. Electric measurements reveal specific properties of ballistic carrier transport, i.e. nonlinear drain voltage-drain current dependence, showing a saturation region, and negative differential resistance at certain bias voltages, which cannot be explained without physical mechanisms related to ballistic transp…
We study field effect transistor characteristics in etched single layer MoS2 nanoribbon devices of width 50nm with ohmic contacts. We employ a SF6 dry plasma process to etch MoS2 nanoribbons using low etching (RF) power allowing very good control over etching rate. Transconductance measurements reveal a steep sub-threshold slope of 3.5V/dec using a global backgate. Moreover, we measure a high current density of 38 uA/um resulting in high on/off ratio of the order of 10^5. We observe mobility reaching as high as 50 cm^2/V.s with increasing source-drain bias.
Coulomb blockade-like transport and enhanced memory in organic transistors embedded with sub-nm Pt nanoparticles for neuromorphic computing
Department of Physics and Astronomy, University of Missouri（密苏里大学物理与天文学系）；MU Materials Science and Engineering Institute, University of Missouri（密苏里大学材料科学与工程研究所）；Department of Electrical Engineering and Computer Science, University of Missouri（密苏里大学电气与计算机工程系）
The shot noise of the current through a single electron transistor (SET), coupled capacitively with an electronic box, is calculated, using the master equation approach. We show that the noise may be sub-Poissonian or strongly super-Poissonian, depending mainly on the box parameters and the gate. The study also supports the idea that not negative differential conductance, but charge accumulation in the quantum dot, responds for the super-Poissonian noise observed.
In order to continue to improve integrated circuit performance and functionality, scaled transistors with short channel lengths and low thickness are needed. But the further scaling of silicon-based devices and the development of alternative semiconductor channel materials that are compatible with current fabrication processes is challenging. Here we report atomic-layer-deposited indium oxide transistors with channel lengths down to 8 nm, channel thicknesses down to 0.5 nm and equivalent dielectric oxide thickness down to 0.84 nm. Due to the scaled device dimensions and low contact resistance,…
We study transport through a Coulomb blockaded topologically nontrivial superconducting wire (with Majorana end states) contacted by metallic leads. An exact formula for the current through this interacting Majorana single-charge transistor is derived in terms of wire spectral functions. A comprehensive picture follows from three different approaches. We find Coulomb oscillations with universal halving of the finite-temperature peak conductance under strong blockade conditions, where the valley conductance mainly comes from elastic cotunneling. The nonlinear conductance exhibits finite-voltage…
A nanoscale device consisting of a metal nanowire, a dielectric, and a gate is proposed. A combination of quantum and thermal stochastic effects enable the device to have multiple functionalities, serving alternately as a transistor, a variable resistor, or a simple resistive element with $I-V$ characteristics that can switch between ohmic and non-ohmic. By manipulating the gate voltage, stochastic transitions between different conducting states of the nanowire can be induced, with a switching time as short as picoseconds. With an appropriate choice of dielectric, the transconductance of the d…
Three terminal single-electron transistor devices utilizing Al/Al2O3 gate electrodes were developed for the study of electron transport through individual single-molecule magnets. The devices were patterned via multiple layers of optical and electron beam lithography. Electromigration induced breaking of the nanowires reliably produces 1-3 nm gaps between which the SMM can be situated. Conductance through a single Mn12(3-thiophenecarboxylate) displays the coulomb blockade effect with several excitations within +/- 40 meV.
We have used a multi-scale physics-based model to predict how the grain size and different grain boundary morphologies of polycrystalline graphene will impact the performance metrics of graphene field-effect transistors. We show that polycrystallinity has a negative impact on the transconductance, which translates to a severe degradation of the maximum and cutoff frequencies. On the other hand, polycrystallinity has a positive impact on current saturation, and a negligible effect on the intrinsic gain. These results reveal the complex role played by graphene grain boundaries, and can be used t…
In the past decade, semiconducting carbon nanotube thin films have been recognized as contending materials for wide-ranging applications in electronics, energy, and sensing. In particular, improvements in large-area flexible electronics have been achieved through independent advances in post-growth processing to resolve metallic versus semiconducting carbon nanotube heterogeneity, in improved gate dielectrics, and in self-assembly processes. Moreover, controlled tuning of specific device components has afforded fundamental probes of the trade-offs between materials properties and device perfor…
We report the operation of a field-effect transistor based on a single InAs nanowire gated by an ionic liquid. Liquid gating yields very efficient carrier modulation with a transconductance value thirty time larger than standard back gating with the SiO2 /Si++ substrate. Thanks to this wide modulation we show the controlled evolution from semiconductor to metallic-like behavior in the nanowire. This work provides the first systematic study of ionic-liquid gating in electronic devices based on individual III-V semiconductor nanowires: we argue this architecture opens the way to a wide range of …
We report silicon delta doping in Gallium Oxide (\b{eta}-Ga2O3) grown by plasma assisted molecular beam epitaxy using a shutter pulsing technique. We describe growth procedures that can be used to realize high Si incorporation in an oxidizing oxygen plasma environment. Delta doping was used to realize thin (12 nm) low-resistance layers with sheet resistance of 320 Ohm/square (mobility of 83 cm^2/Vs, integrated sheet charge of 2.4x10^14 cm^-2). A single delta-doped sheet of carriers was employed as a channel to realize a field effect transistor with current ID,MAX =292 mA/mm and transconductanc…
The effects of an atomistic interface roughness in n-type silicon nanowire transistors (SiNWT) on the radio frequency performance are analyzed. Interface roughness scattering (IRS) is statistically investigated through a three dimensional full-band quantum transport simulation based on the sp3d5s?* tight-binding model. As the diameter of the SiNWT is scaled down below 3 nm, IRS causes a significant reduction of the cut-off frequency. The fluctuations of the conduction band edge due to the rough surface lead to a reflection of electrons through mode-mismatch. This effect reduces the velocity of…
We measure top-gated graphene field effect transistors (GFETs) with nanosecond-range pulsed gate and drain voltages. Due to high-k dielectric or graphene imperfections, the drain current decreases ~10% over time scales of ~10 us, consistent with charge trapping mechanisms. Pulsed operation leads to hysteresis-free I-V characteristics, which are studied with pulses as short as 75 ns and 150 ns at the drain and gate, respectively. The pulsed operation enables reliable extraction of GFET intrinsic transconductance and mobility values independent of sweep direction, which are up to a factor of two…
A small-signal equivalent circuit of 2D-material based field-effect transistors is presented. Charge conservation and non-reciprocal capacitances have been assumed so the model can be used to make reliable predictions at both device and circuit levels. In this context, explicit and exact analytical expressions of the main radio-frequency figures of merit of these devices are given. Moreover, a direct parameter extraction methodology is provided based on S-parameter measurements. In addition to the intrinsic capacitances, transconductance and output conductance, our approach allows extracting t…
We demonstrate a tunnel field effect transistor based on a lateral heterostructure patterned from an $\mathrm{LaAlO_3/SrTiO_3}$ electron gas. Charge is injected by tunneling from the $\mathrm{LaAlO_3}$/$\mathrm{SrTiO_3}$ contacts and the current through a narrow channel of insulating $\mathrm{SrTiO_3}$ is controlled via an electrostatic side gate. Drain-source I/V-curves have been measured at low and elevated temperatures. The transistor shows strong electric-field and temperature-dependent behaviour with a steep sub-threshold slope %of up to as small as $10\:\mathrm{mV/decade}$ and a transcon…
We report on the first realization of Nb-based \textit{all-metallic} gated Dayem nano-bridge field-effect transistors (Nb-FETs). These Josephson devices operate up to a temperature of $\sim 3$ K, and exhibit full suppression of the supercurrent thanks to the application of a control gate voltage. The dependence of the kinetic inductance and of the transconductance on gate voltage promises a performance already on par with so far realized metallic Josephson transistors, and let to foresee the implementation of a superconducting digital logic based on Nb-FETs. We conclude by showing the practica…
We report low-temperature electrical transport studies of molecule-scale silicon nanowires. Individual nanowires exhibit well-defined Coulomb blockade oscillations characteristic of charge addition to a single nanostructure with length scales up to at least 400 nm. Further studies demonstrate coherent charge transport through discrete single particle quantum levels extending the whole device, and show that the ground state spin configuration follows the Lieb-Mattis theorem. In addition, depletion of the nanowires suggests that phase coherent single-dot characteristics are accessible in a regim…
Metallic nanoparticles offer possibilities to build basic electric devices with new functionality and improved performance. Due to the small volume and the resulting low self-capacitance, each single nanoparticle exhibits a high charging energy. Thus, a Coulomb-energy gap emerges during transport experiments that can be shifted by electric fields, allowing for charge transport whenever energy levels of neighboring particles match. Hence, the state of the device changes sequentially between conducting and non-conducting instead of just one transition from conducting to pinch-off as in semicondu…
We develop the two-instanton approximation to the current-voltage characteristic of a single electron transistor within the Ambegaokar-Eckern-Schön model. We determine the temperature and gate voltage dependence of the Coulomb blockade oscillations of the conductance and the effective charge. We find that a small (in comparison with the charging energy) bias voltage leads to significant suppression of the Coulomb blockade oscillations and to appearance of the bias-dependent phase shift.
