Aharonov Bohm Effect in Graphene Fabry Pérot Quantum Hall Interferometers
Yuval Ronen, Thomas Werkmeister, Danial Najafabadi, Andrew T. Pierce, Laurel E. Anderson, Young J. Shin, Si Young Lee, Young Hee Lee, Bobae Johnson, Kenji Watan… 展开作者
Yuval Ronen, Thomas Werkmeister, Danial Najafabadi, Andrew T. Pierce, Laurel E. Anderson, Young J. Shin, Si Young Lee, Young Hee Lee, Bobae Johnson, Kenji Watanabe, Takashi Taniguchi, Amir Yacoby, Philip Kim
Quantum interferometers are powerful tools for probing the wave-nature and exchange statistics of indistinguishable particles. Of particular interest are interferometers formed by the chiral, one-dimensional (1D) edge channels of the quantum Hall effect (QHE) that guide electrons without dissipation. Using quantum point contacts (QPCs) as beamsplitters, these 1D channels can be split and recombined, enabling interference of charged particles. Such quantum Hall interferometers (QHIs) can be used for studying exchange statistics of anyonic quasiparticles. In this study we develop a robust QHI fabrication technique in van der Waals (vdW) materials and realize a graphene-based Fabry-Pérot (FP) QHI. By careful heterostructure design, we are able to measure pure Aharonov-Bohm (AB) interference effect in the integer QHE, a major technical challenge in finite size FP interferometers. We find that integer edge modes exhibit high visibility interference due to relatively large velocities and long phase coherence lengths. Our QHI with tunable QPCs presents a versatile platform for interferometer studies in vdW materials and enables future experiments in the fractional QHE.
Quantum-mechanical calculations of electron magneto-transport in ideal graphene nanoribbons are presented. In noninteracting theory, it is predicted that an ideal ribbon that is attached to wide leads should reveal Fabry-Perot conductance oscillations in magnetic field. In the theory with Coulomb interaction taken into account, the oscillation pattern should rather be determined by the Aharonov-Bohm interference effect. Both of these theories predict the formation of quasi-bound states, albeit of different structures, inside the ribbon because of strong electron scattering on the interfaces be…
The charge and exchange statistics of an elementary excitation manifest in quantum coherent oscillations that can be explored in interferometry measurements. Quantum Hall interferometers are primary tools to uncover unconventional quantum statistics associated with fractional and non-Abelian anyons of a two-dimensional system, the latter being the foundation of topological quantum computing. Graphene interferometers offer new avenues to explore the physics of exotic excitations due to their relatively small charging energies and sharp confinement potentials. Bilayer graphene possesses a true b…
We demonstrate operation of a small Fabry-Perot interferometer in which highly coherent Aharonov-Bohm oscillations are observed in the integer and fractional quantum Hall regimes. Using a novel heterostructure design, Coulomb effects are drastically suppressed. Coherency of edge mode interference is characterized by the energy scale for thermal damping, ${T_0=206}mK$ at $ν=1$. Selective backscattering of edge modes originating in the ${N=0,1,2}$ Landau levels allows for independent determination of inner and outer edge mode velocities. Clear Aharonov-Bohm oscillations are observed at fractiona…
Electron interferometry with quantum Hall edge channels holds promise for probing and harnessing exotic exchange statistics of non-Abelian anyons. In semiconductor heterostructures, however, quantum Hall interferometry has proven challenging and often obscured by charging effects. Here we show that high-mobility monolayer graphene equipped with a series of gate-tunable quantum point contacts that act as electron beam-splitters provides a model system to perform Fabry-Pérot quantum Hall interferometry. We observe high-visibility Aharonov-Bohm interference free of charging effects and widely tun…
We investigate the chemical reactivity of molecular populations confined inside a nanofluidic Fabry-P{é}rot cavity. Due to strong light-matter interactions developing between a resonant electromagnetic cavity-mode and the electric dipole moment of the confined molecules, a polariton is formed. The former gets dressed by environmental vibrational and rotational degrees of freedom of the solvent. We call the resulting polariton dressed by its cloud of environmental excitation a ''reacton'', since it further undergoes chemical reactions. We characterize how the reacton formation modifies the kine…
Three-dimensional topological insulator (3D TI) nanowires display various interesting magnetotransport properties that can be attributed to their spin-momentum-locked surface states such as quasiballistic transport and Aharonov-Bohm oscillations. Here, we focus on the transport properties of a 3D TI nanowire with a gated section that forms an electronic Fabry-Pérot (FP) interferometer that can be tuned to act as a surface-state filter or energy barrier. By tuning the carrier density and length of the gated section of the wire, the interference pattern can be controlled and the nanowire can bec…
Utilizing an electronic Fabry-Perot interferometer in which Coulomb charging effects are suppressed, we report experimental observation of anyonic braiding statistics for the $ν=1/3$ fractional quantum Hall state. Strong Aharonov-Bohm interference of the $ν=1/3$ edge mode is punctuated by discrete phase slips consistent with an anyonic phase of $θ_{anyon}=\frac{2π}{3}$. Our results are consistent with a recent theory of a Fabry-Perot interferometer operated in a regime in which device charging energy is small compared to the energy of formation of charged quasiparticles. Close correspondence b…
We propose an intrinsic 3D Fabry-Pérot type interferometer, coined "higher-order interferometer", that utilizes the chiral hinge states of second-order topological insulators and cannot be equivalently mapped to 2D space because of higher-order topology. Quantum interference patterns in the two-terminal conductance of this interferometer are controllable not only by tuning the strength but also, particularly, by rotating the direction of the magnetic field applied perpendicularly to the transport direction. Remarkably, the conductance exhibits a characteristic beating pattern with multiple fre…
The Role of Interactions in an Electronic Fabry-Perot Interferometer Operating in the Quantum Hall Effect Regime
边缘通道干涉有望成为研究量子霍尔效应（QHE）中带电准粒子统计的重要工具[A. Stern（2008），Ann.Phys.1：204; C. Chamon等人（1997），Phys.Rev.B，55：2331]。本文详细研究了一种工作在QHE区的电子法布里-珀罗干涉仪（FPI）[C。Chamon等人（1997），Phys.Rev.B，55：2331]，其中干扰准粒子的相位由Aharonov-Bohm（AB）效应控制。我们的主要发现是，电子之间的库仑相互作用占主导地位的干扰，即使在一个相对较大的面积FPI，导致强烈的依赖于由磁场上的干扰环所包围的区域。特别是，对于复合边缘结构，与几个独立的边缘通道沿边缘传播，干扰的最外边缘通道（属于最低的朗道水平）是不敏感的磁场，这表明一个恒定的封闭通量。然而，当任何内边缘通道干扰时，当磁场增加时，封闭的通量减小。通过有意地改变具有偏置金属栅极的封闭区域并观察干涉图案的周期性，发现电荷e（对于整数填充因子）和e/3（对于分数填充因子）从FPI排出。此外，这些观测也提供了一种新的方法来检测干扰准粒子的电荷。
Quantum Hall interferometers have been used to probe fractional charge, and more recently, fractional statistics of quasiparticles. Theoretical predictions have been made regarding the effect of electrostatic coupling on interferometer behavior and observation of anyonic phases. Here we present measurements of a small Fabry-Perot interferometer in which these electrostatic coupling constants can be determined experimentally, facilitating quantitative comparison with theory. At the $ν= 1/3$ fractional quantum Hall state, this device exhibits Aharonov-Bohm interference near the center of the con…
The emergence of interference is observed in the resistance of a graphene annulus pn junction device as a result of applying two separate gate voltages. The observed resistance patterns are carefully inspected, and it is determined that the position of the peaks resulting from those patterns are independent of temperature and magnetic field. Furthermore, these patterns are not attributable to Aharonov-Bohm oscillations, Fabry Perot interference at the junction, or moiré potentials. The device data are compared with those of another device fabricated with a traditional Hall bar geometry, as wel…
Quantum Hall (QH) interferometry provides an archetypal platform for the experimental realization of braiding statistics of fractional QH states. However, the complexity of observing fractional statistics requires phase coherence over the length of the interferometer, as well as suppression of Coulomb charging energy. Here, we demonstrate a new type of QH interferometer based on marginally twisted bilayer graphene (mtBLG), with a twist angle $θ$ $\approx$ $0.16$ $^{\circ}$. With the device operating in the QH regime, we observe distinct signatures of electronic Fabry-Pérot (FP) and Aharonov-Bo…
The ability to detect and distinguish quantum interference signatures is important for both fundamental research and for the realization of devices including electron resonators, interferometers and interference-based spin filters. Consistent with the principles of subwavelength optics, the wave nature of electrons can give rise to various types of interference effects, such as Fabry-Pérot resonances, Fano resonances and the Aharonov-Bohm effect. Quantum-interference conductance oscillations have indeed been predicted for multiwall carbon nanotube shuttles and telescopes, and arise from atomic…
