Negative Magnetoresistance in Viscous Flow of Two-Dimensional Electrons

Alekseev, P. S.

doi:10.1103/physrevlett.117.166601

Cited by 205 publications

(252 citation statements)

References 33 publications

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“…In order to do so, it is convenient to inject a microscopically derived magnetic field dependence of the viscosities in the above hydrodynamic solutions. The following dependence was found by Alekseev [14]:…”

Section: Arxiv:170307325v1 [Cond-matstr-el] 21 Mar 2017mentioning

confidence: 67%

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Hydrodynamic Electron Flow and Hall Viscosity

et al. 2017

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In metallic samples of small enough size and sufficiently strong momentum-conserving scattering, the viscosity of the electron gas can become the dominant process governing transport. In this regime, momentum is a long-lived quantity whose evolution is described by an emergent hydrodynamical theory. Furthermore, breaking time-reversal symmetry leads to the appearance of an odd component to the viscosity called the Hall viscosity, which has attracted considerable attention recently due to its quantized nature in gapped systems but still eludes experimental confirmation. Based on microscopic calculations, we discuss how to measure the effects of both the even and odd components of the viscosity using hydrodynamic electronic transport in mesoscopic samples under applied magnetic fields.The semiclassical theory of electronic conduction, based on relaxation of total momentum by impurities, phonons and umklapp scattering, occupies a central place in condensed matter physics. It is therefore of particular interest to study the cases for which it fails. One case that has attracted much interest is the possibility of a hydrodynamic regime, where transport is dominated by viscous effects . One needs a large separation of scales between momentum-relaxing and momentum-conserving scattering in order to see these effects. This was recently achieved in graphene [23,24] and PdCoO 2 [25,26].Interest in such a hydrodynamic regime also emanated from a conjectured bound on diffusion constants for the hydrodynamics of strongly interacting quantum systems [27,28]. Even though the physics described in this work is semiclassical and probably still quite far from these quantum-mechanical bounds, the observations that we hope to stimulate would constitute an important first step towards the understanding of emergent hydrodynamical regimes in electronic systems.A further motivation for the work is that reaching a viscous regime for a charged fluid enables one to break time-reversal symmetry by adding a magnetic field and hence to study a non-dissipative component to the viscosity tensor called the Hall viscosity. The recent interest in this Hall viscosity emanates from the fact that it is topologically quantized in gapped systems [29]. In order to study this effect experimentally, in analogy with the Hall conductivity, the first step would obviously be to measure the classical Hall viscosity. We show in this letter how this measurement could be done by describing specific size effects from Hall viscosity in transport in restricted 2D channels under transverse magnetic fields. This paper is organized as follows. We start by assuming a perfect hydrodynamic regime and calculate ρ xx and ρ xy . We show that the 1/W 2 component of ρ xy is proportional to the Hall viscosity, thereby providing a way of measuring it. In order to have realistic predictions to compare with experiments, one should also take into account other, non-viscous effects that can lead to a sizedependent resistivity. We thus perform a kinetic Boltzmann calculation in which t...

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Section: Arxiv:170307325v1 [Cond-matstr-el] 21 Mar 2017mentioning

confidence: 67%

“…In this limit, the momentum density of the electron gas is conserved and one can write a hydrodynamic equation to model its dynamics [14] [31]:…”

Section: Fluid Equationmentioning

confidence: 99%

Hydrodynamic Electron Flow and Hall Viscosity

et al. 2017

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“…Charge transport in such systems can be described by a set of macroscopic equations that are typically obtained by integrating the kinetic (Boltzmann) equation 12,13,48 . In the disorder-dominated regime such a theory can be reduced to a generalized Ohm's law.…”

Section: Compensated Semimetals In Two Dimensional Strip Geometrymentioning

confidence: 99%

“…Unlike the single-component fluid considered in Ref. 12, these two fluids cannot be considered as incompressible. However, under the assumption (5) electron-hole recombination dominates the viscous compressibility (related to bulk viscosity) allowing us to drop the latter from Eqs.…”

Section: Compensated Semimetals In Two Dimensional Strip Geometrymentioning

confidence: 99%

“…At the same time, viscous one-component systems are characterized by negative MR 11,12 . Here we show that neutral two-component systems may exhibit both types of behavior at the same time so that the MR is non-monotonous: in weak magnetic fields, we find the negative, parabolic MR, while in strong fields the resistance grows with the field eventually approaching the linear dependence.…”

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confidence: 99%

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Nonmonotonic magnetoresistance of a two-dimensional viscous electron-hole fluid in a confined geometry

et al. 2018

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Ultra-pure conductors may exhibit hydrodynamic transport where the collective motion of charge carriers resembles the flow of a viscous fluid. In a confined geometry (e.g., in ultra-high quality nanostructures) the electronic fluid assumes a Poiseuille-like flow. Applying an external magnetic field tends to diminish viscous effects leading to large negative magnetoresistance. In two-component systems near charge neutrality the hydrodynamic flow of charge carriers is strongly affected by the mutual friction between the two constituents. At low fields, the magnetoresistance is negative, however at high fields the interplay between electron-hole scattering, recombination, and viscosity results in a dramatic change of the flow profile: the magnetoresistance changes its sign and eventually becomes linear in very high fields. This novel non-monotonic magnetoresistance can be used as a fingerprint to detect viscous flow in two-component conducting systems.The independent particle approximation 1,2 has dominated the solid state physics for nearly a century. While clearly successful in describing most of the basic transport phenomena in metals and semiconductors, this approach completely neglects Coulomb interaction between charge carriers (the latter is frequently said to be justified by the "weakness" of electron-electron interaction due to, e.g., screening or statistical effects). To be more specific, in many conventional conductors the typical interaction length scale, ee , is too long in comparison to other relevant scales in the system. In particular, at low temperatures the dominant scattering process is due to potential disorder and hence the shortest length scale is the mean free path, dis ee , which determines the residual Drude resistivity at T = 0. At high temperatures, the electron-phonon interaction dominates, ph ee . If these two temperature regimes overlap, then indeed (at least, away from any phase transitions) the role of electron-electron interaction is reduced to small corrections. However, if there exists a temperature window where ee dis , ph , then in that case the independent particle approximation is violated: the motion of charge carriers becomes collective (or hydrodynamic) and hence transport properties of the system are determined by interaction 3 .Signatures of the hydrodynamic behavior have been observed in recent experiments in graphene 4-6 and palladium cobaltate 7 . The effect of external magnetic field on electronic transport in systems with ee dis , ph was studied in magnetotransport measurements in ultra-highmobility GaAs quantum wells 8-10 and more recently in the Weyl semimetal WP 2 11 reporting, in both cases, large negative magnetoresistance. A detailed account of the history of magnetotransport measurements is beyond the scope of this paper. Here we only stress the following well known facts: at the single-particle level, there is no classical magnetoresistance (MR) in single-band (or one-component) systems; taking into account more than one band of carriers (e.g., in semiconduct...

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Quasi‐1D van der Waals Antiferromagnetic CrZr₄Te₁₄ with Large In‐Plane Anisotropic Negative Magnetoresistance

et al. 2022

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The discovery of 2D van der Waals (vdW) magnetic materials is of great significance to explore intriguing 2D magnetic physics and develop innovative spintronic devices. In this work, a new quasi‐1D vdW layered compound CrZr4Te14 is successfully synthesized. Owing to the existence of 1D [CrTe2] and [ZrTe3] chains along the b‐axis, CrZr4Te14 crystals show strong anisotropy of phonon vibrations, electrical transport, and magnetism. Density functional theory calculations reveal the ferromagnetic (FM) coupling within the [CrTe2] chain, while the interchain and interlayer couplings are both weakly antiferromagnetic (AF). Notably, a large intrinsic negative magnetoresistance (nMR) of −56% is achieved at 2 K under 9 T, and the in‐plane anisotropic factor of nMR can reach up to 8.2 in the CrZr4Te14 device. The 1D FM chains and anisotropic nMR effect make CrZr4Te14 an interesting platform for exploring novel polarization‐sensitive spintronics.

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Negative Magnetoresistance in Viscous Flow of Two-Dimensional Electrons

Cited by 205 publications

References 33 publications

Hydrodynamic Electron Flow and Hall Viscosity

Hydrodynamic Electron Flow and Hall Viscosity

Nonmonotonic magnetoresistance of a two-dimensional viscous electron-hole fluid in a confined geometry

Quasi‐1D van der Waals Antiferromagnetic CrZr₄Te₁₄ with Large In‐Plane Anisotropic Negative Magnetoresistance

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Negative Magnetoresistance in Viscous Flow of Two-Dimensional Electrons

Cited by 205 publications

References 33 publications

Hydrodynamic Electron Flow and Hall Viscosity

Hydrodynamic Electron Flow and Hall Viscosity

Nonmonotonic magnetoresistance of a two-dimensional viscous electron-hole fluid in a confined geometry

Quasi‐1D van der Waals Antiferromagnetic CrZr4Te14 with Large In‐Plane Anisotropic Negative Magnetoresistance

Contact Info

Product

Resources

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Quasi‐1D van der Waals Antiferromagnetic CrZr₄Te₁₄ with Large In‐Plane Anisotropic Negative Magnetoresistance