Daniil Asafov | Searcharxiv

arXiv2024

Collapse of Landau level in semi-Dirac materials

Two-dimensional semi-Dirac models describe a family of novel materials that have anisotropic dispersion with relativistic-type spectrum along one of the spatial directions and non-relativistic along another. In the present paper we perform a detailed analysis of Landau levels collapse for such models in perpendicular magnetic field and in-plane electric field by using semi-classical approach and tight-binding simulations. The anisotropic nature of semi-Dirac dispersion manifests itself in the possibility of Landau level collapse for only one of the electric field directions. In addition, the topological transition with merging Dirac cones has its own distinct features in Landau level collapse.

cond-mat.mes-hall↗

arXiv2022

Viscous flow through a finite-width slit: Boundary conditions and dissipation

We study the hydrodynamic viscous electronic transport in a two-dimensional sample separated into two semi-infinite planes by a one-dimensional infinite barrier. The semi-infinite planes are electrically connected via the finite-size slit in the barrier. We calculate the current through the slit assuming finite voltage drop between the planes and neglecting disorder-induced Ohmic resistance, so that dissipation and resistance are purely viscosity-induced. We find that the only solution to the Stokes equation in this geometry, which yields a finite dissipation at finite resistance (and, hence, is not self-contradictory), is the one that fulfills both the no-stress and no-slip boundary conditions simultaneously. As a remarkable consequence, the obtained velocity profile satisfies the so-called "partial-slip" (Maxwell) boundary condition for any value of the slip length, which drops out from all final results. We also calculate the electronic temperature profile for the small and large heat conductivity, and find asymmetric (with respect to the barrier) temperature patterns in the former case.

cond-mat.mes-hall↗