Understanding limits to mobility in ultrahigh-mobility GaAs two-dimensional electron systems: 100 million 
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 and beyond

Chung, Yoon Jang; Gupta, Adbhut; Baldwin, K. W.; West, K. W.; Shayegan, M.; Pfeiffer, L. N.

doi:10.1103/physrevb.106.075134

Cited by 18 publications

(6 citation statements)

References 57 publications

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“…The second constraint is removed due to the increasing availability of semiconductor heterostructures whose 2DEG mobilities are ≈10 7 cm 2 /Vs [ 17 ]. The quantum mean free path of charge carriers in such samples exceeds several micrometers [ 37 , 38 , 39 , 40 ], implying that large-period light-induced LSLs become suitable for experiments both at low magnetic fields and in the fractional quantum Hall effect regime [ 7 , 15 ].…”

Section: Discussionmentioning

confidence: 99%

“…The QW was sandwiched between two δ-doping layers positioned 314 nm and 610 nm below the surface, whereas the center of the QW was 460 nm below the surface. The δ-doping layers were deposited in order to achieve an ultrahigh-mobility (≈1.1 × 10 7 cm 2 /Vs) of the 2DEG confined in the GaAs layer [ 17 ]. A Hall bar was then fabricated by photolithography on the QW structure ( Figure 1 b).…”

Section: Methodsmentioning

confidence: 99%

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An Optical Technique to Produce Embedded Quantum Structures in Semiconductors

et al. 2023

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The performance of a semiconductor quantum-electronic device ultimately depends on the quality of the semiconductor materials it is made of and on how well the device is isolated from electrostatic fluctuations caused by unavoidable surface charges and other sources of electric noise. Current technology to fabricate quantum semiconductor devices relies on surface gates which impose strong limitations on the maximum distance from the surface where the confining electrostatic potentials can be engineered. Surface gates also introduce strain fields which cause imperfections in the semiconductor crystal structure. Another way to create confining electrostatic potentials inside semiconductors is by means of light and photosensitive dopants. Light can be structured in the form of perfectly parallel sheets of high and low intensity which can penetrate deep into a semiconductor and, importantly, light does not deteriorate the quality of the semiconductor crystal. In this work, we employ these important properties of structured light to form metastable states of photo-sensitive impurities inside a GaAs/AlGaAs quantum well structure in order to create persistent periodic electrostatic potentials at large predetermined distances from the sample surface. The amplitude of the light-induced potential is controlled by gradually increasing the light fluence at the sample surface and simultaneously measuring the amplitude of Weiss commensurability oscillations in the magnetoresistivity.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

An Optical Technique to Produce Embedded Quantum Structures in Semiconductors

et al. 2023

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“…This is due to various factors: among the technical ones, the use of microelectronics industry growth and processing techniques has allowed obtaining high quality 2DEGs on wafer scale, that can be electrically connected using highly transparent ohmic contacts [14]. Due to the low mass of the electrons in the conduction band, very high mobilities have been achieved [15]. Record electron mobilities are µ > 50 • 10 6 cm 2 (Vs) −1 yielding macroscopic mean-free paths l mfp > 250 µm.…”

Section: Traditional Quantum Optics In a 2degmentioning

confidence: 99%

Electron wave and quantum optics in graphene

Chakraborti,

Gorini,

Knothe

et al. 2024

J. Phys.: Condens. Matter

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In the last decade, graphene has become an exciting platform for electron optical experiments, in some aspects superior to conventional two-dimensional electron gases (2DEGs). A major advantage, besides the ultra-large mobilities, is the fine control over the electrostatics,which gives the possibility of realising gap-less and compact p-n interfaces with high precision. The latter host non-trivial states, \eg, snake states in moderate magnetic fields, and serve as building blocks of complex electron interferometers. Thanks to the Dirac spectrum and its non-trivial Berry phase, the internal (valley and sublattice) degrees of freedom, and the possibility to tailor the band structure using proximity effects, such interferometers open up a completely new playground based on novel device architectures. In this review, we introduce the theoretical background of graphene electron optics, fabrication methods used to realise electron-optical devices, and techniques for corresponding numerical simulations. Based on this, we give a comprehensive review of ballistic transport experiments and simple building blocks of electron optical devices both in single and bilayer graphene, highlighting the novel physics that is brought in compared to conventional 2DEGs. After describing the different magnetic field regimes in graphene p-n junctions and nanostructures, we conclude by discussing the state of the art in graphene-based Mach-Zender and Fabry-Perot interferometers.

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“…Over the last two decades, great progress has been achieved in increasing the electron mobility in two-dimensional electron gases formed in MBE-grown materials such as GaA/AlGaAs and alternatively in exfoliated graphene. Spectacularly, the electron mobility in GaAs/AlGaAs 2DEGs has recently been reported to reach 57 × 10 6 cm 2 (Vs) −1 1 and, in the absence of phonons at low temperatures, this results in large impurity-dominated mean free path that can exceed 350 μm. These high-mobility 2DEGs are notoriously well described by Fermi liquid theory at low temperatures, but what is perhaps less obvious is that counter-intuitive phenomena can arise due to an interplay between hydrodynamic transport and confinement.…”

Section: Introductionmentioning

confidence: 99%

Anomalous electronic transport in high-mobility Corbino rings

Berkson-Korenberg

et al. 2023

Nat Commun

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We report low-temperature electronic transport measurements performed in two multi-terminal Corbino samples formed in GaAs/Al-GaAs two-dimensional electron gases (2DEG) with both ultra-high electron mobility ( ≳ 20 × 106 cm2/ Vs) and with distinct electron density of 1.7 and 3.6 × 1011 cm−2. In both Corbino samples, a non-monotonic behavior is observed in the temperature dependence of the resistance below 1 K. Surprisingly, a sharp decrease in resistance is observed with increasing temperature in the sample with lower electron density, whereas an opposite behavior is observed in the sample with higher density. To investigate further, transport measurements were performed in large van der Pauw samples having identical heterostructures, and as expected they exhibit resistivity that is monotonic with temperature. Finally, we discuss the results in terms of various lengthscales leading to ballistic and hydrodynamic electronic transport, as well as a possible Gurzhi effect.

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Understanding limits to mobility in ultrahigh-mobility GaAs two-dimensional electron systems: 100 million cm2/Vs and beyond

Cited by 18 publications

References 57 publications

An Optical Technique to Produce Embedded Quantum Structures in Semiconductors

An Optical Technique to Produce Embedded Quantum Structures in Semiconductors

Electron wave and quantum optics in graphene

Anomalous electronic transport in high-mobility Corbino rings

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