Quantum thermal transport in stanene

TL;DR

This paper investigates quantum thermal conductance in stanene, revealing unique behaviors due to Dirac fermions, including a violation of the Wiedemann-Franz law and comparable heat transport by electrons and phonons.

Contribution

It provides the first analysis of quantum thermal transport in stanene, highlighting the impact of Dirac fermions on thermal conductance and challenging existing laws.

Findings

Electron thermal conductance depends on chemical potential.

Wiedemann-Franz law is violated in stanene.

Electrons and phonons carry comparable heat currents.

Abstract

By way of the non-equilibrium Green's function simulations and analytical expressions, the quantum thermal conductance of stanene is studied. We find that, due to the existence of Dirac fermion in stanene, the ratio of electron thermal conductance and electric conductance becomes a chemical-potential-dependent quantity, violating the Wiedemann-Franz law. This finding is applicable to any two-dimensional (2D) materials that possess massless Dirac fermions. In strong contrast to the negligible electronic contribution in graphene, surprisingly, the electrons and phonons in stanene carry a comparable heat current. The unusual behaviours in stanene widen our knowledge of quantum thermal transport in 2D materials.