Finite-temperature pseudospin torque effect in graphene bilayers

We use self-consistent quantum transport theory to investigate the influence of layer Fermi energy and temperature on the interlayer transport properties of bilayer graphene in the regime of excitonic superfluidity. We conclude that at low temperature the critical tunneling currents and quasiparticle penetration depths are well explained by the existing zero-temperature pseudospin torque model. However, when the thermal broadening associated with finite-temperature transport is included, we find that modes injected above the gap lead to increased critical interlayer currents and quasiparticle penetration in to the gapped regime beyond what current analytical models predict. We find that the increases in the critical tunneling current are due to thermal smearing smoothing out the quantum interference effects present at low temperature leading to a slower pseudospin precession about the pseudospin Bloch sphere.