Tuning temperature-dependent of thermal conductivity and heat capacity of two-dimensional GeC compared to Graphene and Germanene: Effects of magnetic field

Abstract

The thermoelectric properties of two-dimensional (2-D) GeC investigated with the next nearest tight binding model in the presence of the vertical magnetic field and the results are compared with the Graphene and Germanene monolayers. The tight binding parameters are obtained from the DFT calculations for the electronic structures. The thermal properties including the heat capacity and thermal conductivity are investigated with the Green function approach and the Kubo-Greenwood formula. Unlike the Graphene and Germanene which become metallic by the magnetic field Π, the GeC remains a semiconductor with band gap reduction in the high magnetic field strength. By applying the magnetic field, the intensity of the DOS spectrum increases around the Fermi level and also the position, height and number of DOS peaks significantly change. For the Graphene and Germanene, the thermal properties increase from zero to its highest value as broad peak at TH and for the GeC monolayer due to its semiconductor properties, the Cv(T) and κ(T) are zero in the lower temperature region and then increase to a peak by further temperature increasing. All cases show strong reduction by the temperature increasing beyond the TH. By applying the magnetic field Π, the increasing rate for the thermal properties increases (decreases) in the lower (higher) temperature region due to the increasing the thermal energy (the scattering and collision) charge carriers.