Circular Hall Effect in a wire

TL;DR

This paper investigates the circular Hall effect in a wire, revealing how carrier viscosity and boundary conditions influence current distribution, magnetic fields, and resistance, leading to a temperature-driven phase transition.

Contribution

It introduces a comprehensive model of the circular Hall effect considering boundary conditions and viscosity, predicting a universal phase transition diagram.

Findings

Carrier viscosity causes current and magnetic field redistribution towards the inner boundary.

Sample resistance vanishes at a threshold temperature, indicating a phase transition.

The theory predicts a universal phase diagram of magnetic field versus temperature.

Abstract

The applied voltage along a wire leads to a constant current density and, in turn, the azimuthal magnetic field. The absence of the radial current in a sample bulk requires nonzero radial(Hall) electric field to be present. We show that the longitudinal current itself is exactly that provided by the carriers drift in crossed azimuthal magnetic and Hall electric field. Nonzero carrier viscosity leads to nonuniform current flow dependent on the boundary condition at the inner wire wall. We find the general boundary condition accounting diamagnetic currents. At low temperatures the enhanced carrier viscosity leads to both the current and azimuthal magnetic field are pushed out the wire bulk towards the inner boundary. Simultaneously, the sample resistance strongly vanishes exhibiting a temperature driven threshold transition. Within low-current limit we calculate the threshold temperature for arbitrary carrier scattering and the sample size. For bulky sample and finite applied current our theory provides the universal phase transition diagram in terms of magnetic field vs temperature.