Electrical conductivity/resistivity σ e (Ω m)/ ρ e (Ω-m), electric thermal conductivity k e (W/m-K) and the Seebeck/Peltier coefficients α S (V/K)/ α P (V) are defined as, σ σ e = 1 ρ ρ e = α α e e , k e = α α t t − − α α t e α α e e − − 1 α α e t T 2 , a n d α α S = α α e t α α e e − − 1 T 2 ( α α S = α α P T ) .