We investigate the temperature and pressure dependences of the electrical resistivity for bcc and hcp Fe using the low-order variational approximation and theoretical transport spectral functions calculated from first principles linear response linear-muffin-tin-orbital method in the generalized-gradient approximation. The calculated values are in close agreement with available experimental data, and show strong increase with temperature and decrease with pressure. We also discuss the behavior of the electrical resistivity for the bcc -> hcp phase transition.
The experimental results of Takaki et al. [1] on the stage I resistivity recovery of electron irradiated iron are analyzed using the analytical theory of diffusion annealing formulated by Simpson & Sossin [2] and Schroeder [3] taking into account the recent first-principles calculations of Fu et al. [4] regarding the mobility of interstitials. Excellent agreement between theory and experiment is obtained by a minimal set of adjustable parameters. The results show that the diffusion annealing equations can be successfully employed for the analysis of recovery experiments in iron.
We report results on electronic transport properties of liquid Fe-S alloys at conditions of planetary cores, computed by first-principle techniques in the Kubo-Greenwood formalism. We describe a combined effect of resistivity saturation due to temperature, compression, and chemistry by comparing the electron mean free path from the Drude response of optical conductivity to the mean interatomic distance. At high compression and high sulfur concentration the Ioffe-Regel condition is satisfied, and the temperature coefficient of resistivity changes sign from positive to negative. We show that thi…
Grain boundaries (GBs) in metals usually increase electrical resistivity due to their distinct atomic arrangement compared to the grain interior. While the GB structure has a crucial influence on the electrical properties, its relationship with resistivity is poorly understood. Here, we perform a systematic study on the resistivity and structure relationship in Cu tilt GBs, employing high resolution in-situ electrical measurements coupled with atomic structure analysis of the GBs. Excess volume and energies of selected GBs are calculated using molecular dynamics simulations. We find a consiste…
We investigate the discontinuous ferromagnetic phase diagram near tricritical point in UCo 1-x Ru x Al compounds by electrical resistivity measurements. Separation of phases in UCo 0.995 Ru 0.005 Al at ambient pressure and in UCo 0.990 Ru 0.010 Al at pressure of 0.2 GPa and disappearance of ferromagnetism at 0.4 GPa is confirmed. The exponent of temperature dependence of electrical resistivity implies change from Fermi liquid behavior to non-Fermi liquid at 0.2 GPa and reaches minimum at 0.4 GPa. Our results are compared to results obtained on the pure UCoAl and explanation for different expon…
The paper presents the first-principle calculation of the electron-phonon coupling and the temperature dependence of the intrinsic electrical resistivity of the zirconium-hydrogen system with various hydrogen concentrations. The nature of the anomalous decrease in the electrical resistivity of the Zr-H system with the increase of hydrogen concentration (at the high concentrations of H/Zr$>$1.5) was studied. It was found that the hydrogen concentration, where the resistivity starts to decrease, is very close to the critical concentration of the $δ-\varepsilon$ phase transition. It was shown tha…
Electrical resistivity evolution during precipitation in Al-Sc alloys is modeled using cluster dynamics. This mesoscopic modeling has already been shown to correctly predict the time evolution of the precipitate size distribution. In this work, we show that it leads too to resistivity predictions in quantitative agreement with experimental data. We only assume that all clusters contribute to the resistivity and that each cluster contribution is proportional to its area. One interesting result is that the resistivity excess observed during coarsening mainly arises from large clusters and not re…
Ductile Regime Machining of semiconductors (DRM) offers higher quality of the resulting surfaces. To optimize this process, it is required to understand the thermal kinetics of silicon metallization under pressure. Such understanding is not yet possible since the metallic phases of silicon aren't readily amenable to thermal characterization through direct measurements. This being the case, one has to rely on processing indirect measurement data to deduce refined estimates of the thermal transport properties of pressurized Silicon. A feasible measurement of this sort is the electrical resistivi…
We have prepared iron microwires in a combination of focused electron beam induced deposition (FEBID) and autocatalytic growth from the iron pentacarbonyl, Fe(CO)5, precursor gas under UHV conditions. The electrical transport properties of the microwires were investigated and it was found that the temperature dependence of the longitudinal resistivity (rhoxx) shows a typical metallic behaviour with a room temperature value of about 88 microΩ cm. In order to investigate the magnetotransport properties we have measured the isothermal Hall-resistivities in the range between 4.2 K and 260 K. From …
We report the magnetic properties, electrical resistivity, and Vickers microhardness of as-cast and annealed high-entropy alloys (HEAs) FeCoNiPd and FeCoNiPt with the face-centered cubic structure. The heat treatment at 800 $^{\circ}$C does not largely affect the physical properties in each HEA. The values of the Curie temperature and the saturation moment at 50 K are 955 K and 1.458 $μ_\mathrm{B}$/f.u. for the annealed FeCoNiPd, and 851 K and 1.456 $μ_\mathrm{B}$/f.u. for the annealed FeCoNiPt, respectively. Each HEA is a soft ferromagnet and shows metallic resistivity. The electronic structu…
Based on the first-principles calculations, we study the electron-phonon scattering effect on the resistivity in the zirconium dichalcogenides, $\text{Zr}_{}\text{S}_{2}$ and $\text{Zr}_{}\text{Se}_{2}$, whose electronic band structures possess multiple valleys at conduction band minimum. The computed resistivity exhibits non-linear temperature dependence, especially for $\text{Zr}_{}\text{S}_{2}$, which is also experimentally observed on some TMDCs such as $\text{Ti}_{}\text{S}_{2}$ and $\text{Zr}_{}\text{Se}_{2}$. By performing the decomposition of the contributions of scattering processes, …
We compute the thermal conductivity and electrical resistivity of solid hcp Fe to pressures and temperatures of Earth's core. We find significant contributions from electron-electron scattering, usually neglected at high temperatures in transition metals. Our calculations show a quasi-linear relation between electrical resistivity and temperature for hcp Fe at extreme high pressures. We obtain thermal and electrical conductivities that are consistent with experiments considering reasonable error. The predicted thermal conductivity is reduced from previous estimates that neglect electron-electr…
Achieving a combination of high mechanical strength and high electrical conductivity in low-weight Al alloys requires a full understanding of the relationships between nanoscaled features and physical properties. Grain boundary strengthening through grain size reduction offers some interesting possibilities but is limited by thermal stability issues. Zener pinning by stable nanoscaled particles or grain boundary segregation are well-known strategies for stabilizing grain boundaries. In this study, the Al-Ca system has been selected to investigate the way segregation affects the combination of …
The results of electrical resistivity, heat capacity and magnetic susceptibility behavior of new class of alloys, Ce_{2-x}La_{x}CoSi_{3}, are reported. The x= 0.0 alloy is mixed valent and La substitution for Ce (x= 0.25) induces linear temperature dependence of resistivity at low temperatures, an observation of relevance to the topic of non-Fermi liquid behavior. The modifications of Kondo effect for all the alloys are also presented.
The amount of heat transport from the core, which constrains the dynamics and thermal evolution of the region, depends on the transport properties of iron. Ohta et al.(2016) and Konopkova et al.(2016) measured electrical resistivity and thermal conductivity of iron, respectively, in laser-heated diamond anvil cells (DACs) at relevant Earth's core pressure-temperature (P-T) conditions, and obtained dramatically contradictory results. Here we measure the electrical resistivity of hcp-iron up to ~170 GPa and ~3,000 K using a four-probe van der Pauw method coupled with homogeneous flat-top laser-h…
COMSOL Multiphysics software is used to describe the behavior of the electrical resistivity of several samples with rectangular shape typically used in the Montgomery method. The simulation data obtained using four isotropic conductors allowed us to understand in detail the behavior of the electric potential and electric field of the samples. The results provide an analytical method which can substitute the four-probe method with much more simplicity and precision.
Using quantum molecular dynamics simulations, we show that the electrical and optical properties of fluid iron change drastically from compressed to expanded regime. The simulation results reproduce the main trends of the electrical resistivity along isochores and are found to be in good agreement with experimental data. The transition of expanded fluid iron into a nonmetallic state takes place close to the density at which the constant volume derivative of the electrical resistivity on internal energy becomes negative. The study of the optical conductivity, absorption coefficient, and Rossela…
Opposite impact of thermal expansion and phonon anharmonicity on the phonon-limited resistivity of elemental metals from first principles
European Theoretical Spectroscopy Facility, Institute of Condensed Matter and Nanosciences, Université catholique de Louvain(欧洲理论光谱设施,凝聚态物质与纳米科学研究所,天主教鲁汶大学);Scientific Computing Department, Science and Technology Facilities Council, UK Research and Innovation, Daresbury Laboratory(科学与工程设施理事会英国研究与创新达尔斯伯里实验室科学计算部);Département de Physique et Institut Courtois, Université de Montréal(蒙特利尔大学物理系与库瓦托瓦研究所);Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science(魏茨曼科学研究所分子化学与材料科学系);WEL Research Institute(WEL研究所)
We have performed electrical resistivity and DC magnetization measurements as a function of temperature, on polycrystalline samples of phase separated LaPrCaMnO. We have used the General Effective Medium Theory to obtain theoretical resistivity vs. temperature curves corresponding to different fixed ferromagnetic volume fraction values, assuming that the sample is a mixture of typical metallic like and insulating manganites. By comparing this data with our experimental resistivity curves we have obtained the relative ferromagnetic volume fraction of our sample as a function of temperature. Thi…
We report a study on the electrical properties of 19 nm thick Yttrium Iron Garnet (YIG) films grown by liquid phase epitaxy. The electrical conductivity and Hall coefficient are measured in the high temperature range [300,400]~K using a Van der Pauw four-point probe technique. We find that the electrical resistivity decreases exponentially with increasing temperature following an activated behavior corresponding to a band-gap of $E_g\approx 2$ eV, indicating that epitaxial YIG ultra-thin films behave as large gap semiconductor, and not as electrical insulator. The resistivity drops to about $5…
We have synthesized a large amount of boron-doped multiwalled carbon nanotubes (MWNTs) by hot-filament chemical vapor deposition. The synthesis was carried out in a flask using a methanol solution of boric acid as a source material. The scanning electron microscopy, transmission electron microscopy, and micro-Raman spectroscopy were performed to evaluate the structural properties of the obtained MWNTs. In order to evaluate the electrical properties, temperature dependence of resistivity was measured in an individual MWNTs with four metal electrodes. The Ramman shifts suggest carrier injection …
Half-Heusler(HH) alloys have shown promising thermoelectric properties in the medium and high temperature range. To harness these material properties for thermoelectric applications, it is important to realize electrical contacts with low electrical contact resistivity. However, little is known about the detailed structural and electronic properties of such contacts, and the expected values of contact resistivity. Here, we employ atomistic ab initio calculations to study electrical contacts in a subclass of HH alloys consisting of the compounds HfCoSb, HfZrCoSb, and HfZrNiSn. By using Ag as a …
We present a first-principles study of the temperature- and density-dependent intrinsic electrical resistivity of graphene. We use density-functional theory and density-functional perturbation theory together with very accurate Wannier interpolations to compute all electronic and vibrational properties and electron-phonon coupling matrix elements; the phonon-limited resistivity is then calculated within a Boltzmann-transport approach. An effective tight-binding model, validated against first-principles results, is also used to study the role of electron-electron interactions at the level of ma…
An experimental setup for determining the electrical resistivity of several types of thermoelectric materials over the temperature range 20 < T < 550 C is described in detail. One resistivity measurement during temperature cycling is also explained for Cu0.01Bi2Te2.7Se0.3 while a second measurement is made on Yb0.35Co4Sb12 as a function of time at 400 C. Both measurements confirm that the materials are thermally stable for the temperature range and time period measured. Measurements made during temperature cycling show an irreversible decrease in the electrical resistivity of Cu0.01Bi2Te2.7Se0…
We report the temperature dependent electrical transport properties of gated bilayer graphene devices. We see a clear evidence of insulating behavior due to electron-hole charge puddles. The electrical resistivity increases while the mobility decreases with decreasing temperature, a characteristic due to carrier inhomogeneity in graphene. The theoretical fittings using an empirical formula of single electron tunneling indicate that electrical resistivity follows a universal curve with a scaling parameter. The scaling parameter is determined to be a measure of the fluctuations in the electron-h…
We report the influence of external pressure (P= up to 8 GPa) on the temperature dependence of electrical resistivity of a Yb-based Kondo lattice, YbPd2Si2, which does not undergo magnetic ordering under ambient pressure condition. There are qualitative changes in the temperature dependence of electrical resistivity due to the application of external pressure. While the resistivity is found to vary quadratically below 15 K (down to 45 mK) characteristic of Fermi-liquids, a drop is observed below 0.5 K for P= 1 GPa. Since the resistance values do not attain zero, we are attempted to attribute t…
SrVO3 and SrNbO3 are perovskite-type transition-metal oxides with the same d1 electronic configuration. Although SrNbO3 (4d1) has a larger d orbital than SrVO3 (3d1), the reported electrical resistivity of SrNbO3 is much higher than that of SrVO3, probably owing to nonstoichiometry. In this paper, we grew epitaxial, high-conductivity stoichiometric SrNbO3 using pulsed laser deposition. The growth temperature strongly affected the Sr/Nb ratio and the oxygen content of the films, and we obtained stoichiometric SrNbO3 at a very narrow temperature window around 630 $°$C. The stoichiometric SrNbO3 …
Resistivity saturation is observed in many metallic systems with a large resistivity, i.e., when the resistivity has reached a critical value, its further increase with temperature is substantially reduced. This typically happens when the apparent mean free path is comparable to the interatomic separations - the Ioffe-Regel condition. Recently, several exceptions to this rule have been found. Here, we review experimental results and early theories of resistivity saturation. We then describe more recent theoretical work, addressing cases both where the Ioffe-Regel condition is satisfied and whe…
We report an unusual temperature (T) dependent electrical resistivity($ρ$) behavior in a class of ternary intermetallic compounds of the type RCuAs$_2$ (R= Rare-earths). For some rare-earths (Sm, Gd, Tb and Dy) with negligible 4f-hybridization, there is a pronounced minimum in $ρ$(T) far above respective Néel temperatures (T$_N$). However, for the rare-earths which are more prone to exhibit such a $ρ$(T) minimum due to 4f-covalent mixing and the Kondo effect, this minimum is depressed. These findings, difficult to explain within the hither-to-known concepts, present an interesting scenario in …
Within the Kubo-Greenwood formalism we use the fully relativistic, spin-polarized, screened Korringa-Kohn-Rostoker method together with the coherent-potential approximation for layered systems to calculate the resistivity for the permalloy series Ni$_{c}$Fe$_{1-c}$. We are able to reproduce the variation of the resistivity across the entire series; notably the discontinuous behavior in the vicinity of the structural phase transition from bcc to fcc. The absolute values for the resistivity are within a factor of two of the experimental data. Also the giant magnetoresistance of a series of perma…
The Sn substituted Ni-Zn ferrites were synthesized by the standard double sintering technique using nano powders of nickel oxide (NiO), zinc oxide (ZnO), iron oxide (Fe2O3) and tin oxide (SnO2). The structural and electrical properties have been investigated by the X-ray diffraction, scanning electron microscopy, DC resistivity and dielectric measurements. Extra intermediate phase has been detected along with the inverse cubic spinel phase of Ni-Zn ferrite. Enhancement of grain size is observed in Sn substituted Ni-Zn ferrites. DC resistivity as a function of temperature has been investigated …
We present a microscopic model for systems showing resistivity saturation. An essentially exact quantum Monte-Carlo calculation demonstrates that the model describes saturation. We give a simple explanation for saturation, using charge conservation and considering the limit where thermally excited phonons have destroyed the periodicity. Crucial model features are phonons coupling to the hopping matrix elements and a unit cell with several atoms. We demonstrate the difference to a model of alkali-doped C60 with coupling to the level positions, for which there is no saturation.
The electrical resistivity and the anisotropic magnetoresistance (AMR) was investigated for Ni Co alloys at and below room temperature. The Ni Co alloy layers having a thickness of about 2 um were prepared by electrodeposition on Si wafers with evaporated Cr and Cu underlayers. The alloy composition was varied in the whole concentration range by varying the ratio of Ni sulfate and Co sulfate in the electrolyte. The Ni Co alloy deposits were investigated first in the as deposited state on the substrates and then, by mechanically stripping them from the substrates, as self supporting layers both…
The present work aims to study the effect of ion irradiation on structural and electrical properties and their correlation with the defects in Zn1-xMnxO type system. Zn1-xMnxO (x = 0.02, 0.04) samples have been synthesized by solid-state reaction method and have been irradiated with 50 MeV Li3+ ions. The concomitant changes have been probed by x-ray diffraction (XRD), temperature dependent electrical resistivity and positron annihilation lifetime (PAL) spectroscopy. XRD result shows single phase wurtzite structure for Zn0.98Mn0.02O, whereas for Zn0.96Mn0.04O sample an impurity phase has been f…
In metals, orbital motions of conduction electrons on the Fermi surface are quantized in magnetic fields, which is manifested by quantum oscillations in electrical resistivity. This Landau quantization is generally absent in insulators. Here we report a notable exception in an insulator, ytterbium dodecaboride (YbB12). Despite much larger than that of metals, the resistivity of YbB12 exhibits profound quantum oscillations. This unconventional oscillation is shown to arise from the insulating bulk, yet the temperature dependence of their amplitude follows the conventional Fermi liquid theory of…
We report the electrical resistivity, thermoelectric power, and thermal conductivity of single-crystalline and sintered samples of the 5d pyrochlore oxide CsW2O6. The electrical resistivity of the single crystal is 3 mohm cm at 295 K and gradually increases with decreasing temperature above 215 K (Phase I). The thermoelectric power of the single-crystalline and sintered samples shows a constant value of approximately -60 uV K-1 in Phase I. These results reflect that the electron conduction by W 5d electrons in Phase I is incoherent and in the hopping regime, although a band gap does not open a…
A systematic investigation of La0.67Ca0.33MnO3 manganites has been undertaken, mainly to understand the influence of varying crystallite size (nanometer range) on electrical resistivity, magnetic susceptibility and thermoelectric power. The materials were prepared by the sol-gel method of sintering at four different temperatures between 800 and 1100 degrees C. The samples were characterized by X-ray diffraction and data were analyzed using Rietveld refinement. The metal-insulator transition temperatures (TP) are found to increase with increasing sintering temperatures, while the magnetic trans…
The temperature dependence of the electrical resistivity and magnetoresistance of Xe-ion beam sputtered Fe-Cr multilayers has been investigated. The electrical resistivity between 5 and 300 K in the fully ferromagnetic state, obtained by applying a field beyond the saturation field (H_sat) necessary for the antiferromagnetic(AF)-ferromagnetic(FM) field-induced transition, shows evidence of spin-disorder resistivity as in crystalline Fe and an s-d scattering contribution (as in 3d metals and alloys). The sublattice magnetization m(T) in these multilayers has been calculated in terms of the plan…
In this paper we show that the widely accepted method of the determination of Curie temperature (TC) in (Ga,Mn)As samples, based on the position of the peak in the temperature derivative of the resistivity,completely fails in the case of non-metallic and low-TC unannealed samples. In this case we propose an alternative method, also based on electric transport measurements, which exploits temperature dependence of the second derivative of the resistivity upon magnetic field.
The impedance behavior of pre-oxidized iron in liquid lead-bismuth eutectic (LBE) at 200 oC is studied using electrochemical impedance spectroscopy. The structures and resistance of oxide grown on iron oxidized in air at different temperatures and durations are compared. The results show that the resistance of the oxide film increases with increasing oxidizing temperature, due to the formation of a thicker scale and fewer defects. At the same temperature (600 oC), increasing the oxidation time can also reduce the defect concentration in the oxide film and improve the impedance of the oxide sca…
Understanding the electronic transport properties of iron under high temperatures and pressures is essential for constraining geophysical processes. The difficulty of reliably measuring these properties under Earth-core conditions calls for sophisticated theoretical methods that can support diagnostics. We present results of the electrical conductivity within the pressure and temperature ranges found in Earth's core from simulating microscopic Ohm's law using time-dependent density functional theory. Our predictions provide a new perspective on resolving discrepancies in recent experiments.
Double exchange mechanism is believed to favor transport along ferromagnetic directions, the failure of which in explaining the unusual resistivity anisotropy in iron pnictides is investigated. Several factors intrinsic to the microscopic mechanism of transport in iron pnictides are identified and analyzed, including the moderate Hund's coupling, low local moment, and presence of two anisotropic degenerate orbitals xz and yz. In particular, the substantial second neighbor hoppings are found to be decisive in giving results opposite to the double exchange picture. In high temperature nonmagneti…
Electrically-gated laser-induced spin dynamics in magneto-electric iron garnet at room temperature
Radboud University Nijmegen(拉德堡德大学);Institute for Molecules and Materials(分子与材料研究所);Faculty of Physics, Lomonosov Moscow State University(莫斯科国立大学物理系);MIREA - Russian Technological University(莫斯科信息俄罗斯国立技术大学)
Many transition metal compounds show saturation of the resistivity at high temperatures, T, while the alkali-doped fullerenes and the high-Tc cuprates are usually considered to show no saturation. We present a model of transition metal compounds, showing saturation, and a model of alkali-doped fullerenes, showing no saturation. To analyze the results we use the f-sum rule, which leads to an approximate upper limit for the resistivity at large T. For some systems and at low T, the resistivity increases so rapidly that this upper limit is approached for experimental T. The resistivity then satur…
A detailed investigation on the structural and magneto-transport properties of iron intercalated Bi2Se3 single crystals have been presented. The x-ray diffraction and Raman studies confirm the intercalation of Fe in the van der Waals gaps between the layers. The electrical resistivity of the compounds decreases upon intercalation, and Hall resistivity shows the enhancement of the charge carriers upon intercalation. The magnetoresistance shows the non-saturating linear behavior at higher magnetic field and low temperature. Intercalation of Fe increases the onset of the linear magnetoresistance …
The results of magnetic susceptibility, electrical resistivity ($ρ$), heat-capacity (C) and thermopower (S) measurements on CeCuAs2, forming in ZrCuSi2-type tetragonal structure, are reported. Our investigations reveal that Ce is trivalent and there is no clear evidence for long range magnetic ordering down to 45 mK. The $ρ$ behavior is notable in the sense that (i) the temperature (T)-coefficient of $ρ$ is negative in the entire range of measurement (45 mK to 300 K) with large values of $ρ$, while S behavior is typical of metallic Kondo lattices, and (ii) $ρ$ is proportional to T-0.6 at low t…
Cu${}_{50-x}$Zr${}_{x}$ (x = 50, 54, 60 and 66.6) polycrystalline alloys were prepared by arc-melting. The crystal structure of the ingots has been examined by X-ray diffraction. Non-equilibrium martensitic phases with monoclinic structure were detected in all the alloys except Cu${}_{33.4}$Zr${}_{66.6}$. Temperature dependencies of electrical resistivity in the temperature range of T = 4 - 300 K have been measured as well as room temperature values of Hall coefficients and thermal conductivity. Electrical resistivity demonstrates anomalous behavior. At the temperatures lower than 20 K, their …
We have revealed the decisive role of grain-boundary-induced strain fields in electron scattering in polycrystalline graphene. To this end, we have formulated the model based on Boltzmann transport theory which properly takes into account the microscopic structure of grain boundaries (GB) as a repeated sequence of heptagon-pentagon pairs. The effect of strain field is described within the deformation potential theory. For comparison, we consider the scattering due to electrostatic potential of charged grain boundary. We show that at naturally low GB charges the deformation potential scattering…
The results of dc magnetization, electrical and magnetoresistance and heat capacity measurements (2-300 K) on Tb7Rh3, crystallizing in Th7Fe3-type hexagonal structure, are reported. In this compound, magnetic ordering sets in around 90 K with additional transitions at low temperatures and the temperature coefficient of resistivity (R), dR/dT, is negative over a wide temperature range in the paramagnetic state. The present magnetization results reveal that this compound is apparently characterized by rich features in the magnetic-field-temperature phase diagram. A point of major emphasis is tha…
We calculate the temperature dependence of NMR relaxation rate and electrical resistivity for coupling to a local, strongly anharmonic phonon mode. We argue that the two-phonon Raman process is dominating NMR relaxation. Due to the strong anharmonicity of the phonon an unusual temperature dependence is found having a low temperature peak and becoming constant towards higher temperatures. The electrical resistivity is found to vary like T^2 at low temperatures and following a sqrt{T} behavior at high temperatures. Both results are in qualitative agreement with recent observations on beta-pyroch…
Drastic field-induced resistivity upturns as signatures of unconventional magnetism in superconducting iron chalcogenides
University of Oxford(牛津大学);Max Planck Institute for Solid State Research(马克斯·普朗克固体研究所);Institute of High-Pressure Physics, Polish Academy of Sciences(波兰科学院高压物理研究所);Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology(卡尔斯鲁厄理工学院量子材料与技术研究所)