Conductance suppression due to two-stream instability in bilayer graphene

TL;DR

This paper explores how two-stream instability affects conductance in bilayer graphene, revealing a new electrostatic relaxation mechanism and identifying two distinct transport regimes influenced by temperature, drift velocity, and magnetic fields.

Contribution

It introduces a novel electrostatic mechanism for current relaxation in bilayer graphene and analyzes the impact of two-stream instability on transport properties.

Findings

Identification of a threshold drift speed near thermal velocity

Discovery of a purely electrostatic conductance relaxation mechanism

Correction of Hall conductivity results due to instability effects

Abstract

We investigate the electron-hole two-stream instability (or Coulomb drag) in intrinsic bilayer graphene in the hydrodynamic regime, accounting for the effects of temperature, initial drift velocity, magnetic field, and collisions. The threshold drift speed for the onset of instabilities is of the order of the thermal velocity of the carriers. We put in evidence an unprecedented purely electrostatic mechanism leading to current relaxation, giving rise to a well-defined dc longitudinal conductivity $\propto T^{3/2}$. Due to competition between electrostatic and collisional processes, two distinct transport regimes are identified. An analysis on the Hall conductivity revealed that the two-stream instability effects also correct the most recent results obtained within the linear response theory.