Electronic properties Thermoelectricity Bismuth compounds Bismuth selenide Boltzmann equation Boltzmann transport equation Carrier mobility Density functional theory Density functionaltheory Density of state Electric power factor Electrical conductivity Electricalconductivity Electronic Environmental impact Figure of merit Figure of merits Power factor Seebeck coefficient Selenium compounds Spin-orbit coupling Thermal conductivity Thermoelectric equipment Thermoelectric performance Thermoelectric properties Underrelaxation electrical conductivity electrical property heat source nickel