July 25, 2024
Somayeh Behzad

Somayeh Behzad

Academic rank: Associate professor
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Education: Ph.D in Physics
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Research

Title
Controlling electrical and thermoelectric properties of bilayer SiC by bias voltage
Type Article
Keywords
Density functional theory Tight binding model Electronic structure Thermal properties
Researchers Raad Chegel، Somayeh Behzad

Abstract

The thermoelectric properties of bilayer SiC in the presence of bias voltage are investigated by using the tight binding model. The Green function and the Kubo-Greenwood formula are employed to investigate the temperature dependence of electric and thermal conductivities, heat capacity and paramagnetic susceptibility of biased bilayer SiC. Based on the first-principles calculation of bilayer SiC, we fit the sixth nearest neighbors intralayer and the fourth nearest neighbors interlayer tight-binding model parameters. Bilayer SiC is semiconductor with indirect band gap at K point. The band gap of bilayer SiC decreases linearly with increasing the bias voltage until reaches zero at critical voltage Uc = 2.08 eV, thereafter reopens and increases linearly by further increasing the bias voltage beyond Uc. The thermal functions increase with temperature to maximum then decrease with further temperature increasing. The increase occurs when the thermal energy is sufficient to excite charge carries from the valence bands to the conduction bands. The thermal properties are dependent to the bias voltage and in the low temperature range the biased bilayer SiC has higher thermal properties than that unbiased case, due to the band gap reduction. The thermoelectric figure of merit can be controlled by applying the bias voltage which leads to increasing the high temperature applications of the bilayer SiC.