Resolving Hall and dissipative viscosity ambiguities via boundary effects

Rao, Pranav; Bradlyn, Barry

doi:10.1103/physrevb.107.075148

Cited by 6 publications

(4 citation statements)

References 48 publications

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“…We have presented the hydrodynamics of a two-dimensional fluid with D 6 point group. In contrast to earlier works which focus on the viscosity tensor [16][17][18][19][20][21], we have additionally found a new dissipative coefficient α (and its Onsager partner β), which is allowed by the explicit breaking of spatial-inversion and time-reversal symmetries.…”

Section: Discussioncontrasting

confidence: 97%

“…Because electron hydrodynamics is predominantly controlled by scattering near the Fermi level, the equations of motion are sensitive to the symmetry group realized by the Fermi surface. With only a handful of exceptions [16][17][18][19][20][21], most of the theoretical literature on electron hydrodynamics restricts to isotropic liquids [22][23][24][25][26][27][28][29][30], which have continuous rotational invariance. However, fluids with discrete (finite) rotational point groups may realize hydrodynamic phenomena not possible in isotropic fluids.…”

Section: Introductionmentioning

confidence: 99%

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Hydrodynamics with triangular point group

2023

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When continuous rotational invariance of a two-dimensional fluid is broken to the discrete, dihedral subgroup D_6D6 - the point group of an equilateral triangle - the resulting anisotropic hydrodynamics breaks both spatial-inversion and time-reversal symmetries, while preserving their combination. In this work, we present the hydrodynamics of such D_6D6-symmetric fluids, identifying new symmetry-allowed dissipative terms in the hydrodynamic equations of motion. We propose two experiments - both involving high-purity solid-state materials with D_6D6-invariant Fermi surfaces - that are sensitive to these new coefficients in a D_6D6-invariant electron fluid. In particular, we propose a local current imaging experiment (which is present-day realizable with nitrogen vacancy center magnetometry) in a hexagonal device, whose D_6D6-exploiting boundary conditions enable the unambiguous detection of these novel transport coefficients.

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Section: Discussioncontrasting

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Hydrodynamics with triangular point group

2023

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“…In the hydrodynamic regime, electron transport is governed by the linearized Navier-Stokes equation with a viscous term [22,33,70,71]. The anti-symmetric part of the viscous tensor, Hall viscosity ν H , can emerge in the 2D electron fluid when both time-reversal and parity symmetries are broken by an external magnetic field [24,26,[72][73][74][75][76][77][78][79][80][81][82]. This non-dissipative Hall viscosity ν H was first measured in ultra-clean graphene [23].…”

Section: Hydrodynamic Electron Flow Modelmentioning

confidence: 99%

Optical N-plasmon: topological hydrodynamic excitations in graphene from repulsive Hall viscosity

Sun,

Van Mechelen,

Bharadwaj

et al. 2023

New J. Phys.

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Edge states occurring in Chern and quantum spin-Hall phases are signatures of the topological electronic band structure in two-dimensional (2D) materials. Recently, a new topological electromagnetic phase of graphene characterized by the optical N-invariant was proposed. Optical N-invariant arises from repulsive Hall viscosity in hydrodynamic many-body electron systems, distinct from the Chern and Z2 invariants. In this paper, we introduce the topologically protected edge excitation -- optical N-plasmon of interacting many-body electron systems in the topological optical N-phase. These optical N-plasmons are signatures of the topological plasmonic band structure in 2D materials. We demonstrate that optical N-plasmons exhibit unique dispersion relations, stability against various boundary conditions and edge profiles when compared with the topologically trivial edge magneto plasmons. Based on the optical N-plasmon, we design an ultra sub-wavelength broadband topological hydrodynamic circulator, which is a chiral quantum radio-frequency circuit component crucial for information routing and interfacing quantum-classical computing systems. Furthermore, we reveal that optical N-plasmons can be effectively tuned by the neighboring dielectric environment without breaking the topological properties. Our work provides a smoking gun signature of topological electromagnetic phases occuring in two-dimensional materials arising from repulsive Hall viscosity.

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“…As a consequence, a system inherent correlation between density and vorticity appears in (weakly) compressible chiral active fluids, which was first predicted in theory [53,71,73], and was directly observed experimentally in our recent report [34], allowing a measurement of odd viscosity from the bulk. However, in complex systems with several even and odd contributions to the dynamics, the system behaviour can be much more complicated [74] and vastly different behaviours can be observed in diverse chiral active systems.…”

Section: Introductionmentioning

confidence: 99%