Anisotropic Two-Dimensional Disordered Wigner Solid

Hossain, Md. Shafayat; Ma, Min; Villegas-Rosales, K. A.; Chung, Yoon Jang; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.; Shayegan, M.

doi:10.1103/physrevlett.129.036601

Cited by 21 publications

(6 citation statements)

References 61 publications

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“…For example, in 2D, due to the interplay of the electron-electron (e-e) interaction, the localization phenomena and the Fermi sea anisotropy, anisotropic disordered Wigner crystal has been predicted [7] and some of its signatures has been observed [8]. In 1D, disordered zigzag configurations produced by weakening the 1D confinement and by allowing the electrons to relax in a second dimension has been also reported [9,10].…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Wigner Molecules in Nanowire Y-junctions

Méndez-Camacho

Cruz‐Hernández

2022

Preprint

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The possibility of crystalline states of interacting electrons, known as Wigner crystals, has been intensively studied in each of the three dimensions. One-dimensional (1D) systems, however, can be interconnected forming two-dimensional (2D) lattices, being a three-terminal Y-junction (Y-J) the simplest one. Then, even when electrons in the individual branches of the Y are confined in 1D, as the Y-J is in 2D, one could expect significant differences in the crystalline state of the electron gas in a Y-J. With the recent report of fabrication of defect-free GaAs/AlGaAs Y-Js by epitaxial methods, the study of semiconductor Y-Js acquires a special relevance due to its eventual direct exploration. Here, by considering the collective electron interactions using a Yukawa-like effective potential, we explore a two-electron distribution in nanowire Y-Js by modulating its electron density via a screening parameter. We find that the electrons changes from a quasi-continuous to a Wigner molecule-like distribution when the electron density decreases in the Y-J. In bold contrast to the strict 1D case, where equidistant distributions of equal density are obtained in the Wigner regime, in the Y-J equidistant distributions of asymmetric density are induced. We also explore the effect of an external electric field acting along the Y-axis on the asymmetric distributions.

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Section: Introductionmentioning

confidence: 99%

Asymmetric Wigner Molecules in Nanowire Y-junctions

Méndez-Camacho

Cruz‐Hernández

2022

Preprint

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“…Another system that forms a 2D crystal state that can be driven is electron solids or Wigner crystals [42][43][44][45][46][47][48][49][50][51][52][53]. Solid state systems hosting Wigner crystals usually contain some form of quenched disorder, and a variety of studies have revealed nonlinear transport and possible depinning thresholds [44-46, 48, 54] associated with enhanced noise [51].…”

Section: Introductionmentioning

confidence: 99%

Melting, reentrant ordering and peak effect for Wigner crystals with quenched and thermal disorder

Reichhardt

Reichhardt²

2023

New J. Phys.

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We consider simulations of Wigner crystals in solid state systems interacting with random quenched disorder in the presence of thermal fluctuations. When quenched disorder is absent, there is a well defined melting temperature determined by the proliferation of topological defects, while for zero temperature, there is a critical quenched disorder strength above which topological defects proliferate. When both thermal and quenched disorder are present, these effects compete, and the thermal fluctuations can reduce the effectiveness of the quenched disorder, leading to a reentrant ordered phase in agreement with the predictions of Nelson [Phys. Rev. B 27, 2902 (1983)]. There are two competing theories for the low temperature behavior, and our simulations show that both capture aspects of the actual response. The critical disorder strength separating ordered from disordered states remains finite as the temperature goes to zero, as predicted by Cha and Fertig [Phys. Rev. Lett. 74, 4867 (1995)], instead of dropping to zero as predicted by Nelson. At the same time, the critical disorder strength decreases with decreasing temperature, as predicted by Nelson, instead of remaining constant, as predicted by Cha and Fertig. The onset of the reentrant phase can be deduced based on changes in the transport response, where the reentrant ordering appears as an increase in the mobility or the occurrence of a depinning transition. We also find that when the system is in the ordered state and thermally melts, there is an increase in the effective damping or pinning. This produces a drop in the electron mobility that is similar to the peak effect phenomenon found in superconducting vortices, where thermal effects soften the lattice or break down its elasticity, allowing the particles to better adjust their positions to take full advantage of the quenched disorder.

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“…Of the numerous classical charged systems that form lattice states due to Coulomb interactions, the best known is Wigner crystals of 2D electrons at low densities [29,31,32], which can form in elections on liquid helium [54,55] or in solid-state systems [30,[56][57][58][59][60][61][62][63][64][65]. There have been several studies of 2D Wigner crystals coupled to 1D or quasi-1D nanostructured channels or arrays [66][67][68][69][70][71], while more recently, Wigner crystals coupled to 2D periodic substrates have been studied in moiré heterostructures [72][73][74][75][76][77][78] and dichalcogenide monolayers [79].…”

Section: Introductionmentioning

confidence: 99%

Magnetic field effects and transverse ratchets in charge lattices coupled to asymmetric substrates

Reichhardt,

Reichhardt

2023

New J. Phys.

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We examine a charge lattice coupled to a one-dimensional asymmetric potential in the presence of an applied magnetic ﬁeld, which induces gyrotropic eﬀects in the charge motion. This system could be realized for Wigner crystals in nanostructured samples, dusty plasmas, or other classical charge-ordered states where gyrotropic motion and damping can arise. For zero magnetic ﬁeld, an applied external ac drive can produce a ratchet eﬀect in which the particles move along the easy ﬂow direction of the substrate asymmetry. The zero ﬁeld ratchet eﬀect can only occur when the ac drive is aligned with the substrate asymmetry direction; however, when a magnetic ﬁeld is added, the gyrotropic forces generate a Hall eﬀect that leads to a variety of new behaviors, including a transverse ratchet motion that occurs when the ac drive is perpendicular to the substrate asymmetry direction. We show that this system exhibits commensuration eﬀects as well as reversals in the ratchet eﬀect and the Hall angle of the motion. The magnetic ﬁeld also produces a nonmonotonic ratchet eﬃciency when the particles become localized at high ﬁelds.

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Anisotropic Two-Dimensional Disordered Wigner Solid

Cited by 21 publications

References 61 publications

Asymmetric Wigner Molecules in Nanowire Y-junctions

Asymmetric Wigner Molecules in Nanowire Y-junctions

Melting, reentrant ordering and peak effect for Wigner crystals with quenched and thermal disorder

Magnetic field effects and transverse ratchets in charge lattices coupled to asymmetric substrates

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