Numerical analysis of thermoelectric properties of bismuth under amagnetic field

T. Komine¹, Y. Ishikawa²,A.Suzuki³, H. Shirai⁴, Y. Hasegawa²

¹Department of Media andTelecommunications Engineering, Faculty of Engineering, Ibaraki University,4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan

²Graduate School of Science andEngineering, Saitama University, 255, Shimo-Okubo, Sakura-ku, Saitama 338-8570,Japan

³Northern Laboratory, SaitamaIndustrial Technology Center, 2-133, Suehiro, Saitama 360-0031, Japan

⁴Department ofFunctional Materials Science, Saitama University, 255, Shimo-Okubo, Sakura-ku,Saitama 338-8570, Japan

We study theanisotropic thermoelectric properties of bismuth associated with many-valleybandstructure in magnetic field. Some researchers reported that the appliedmagnetic field enhances Seebeck coefficient and improves figure of merit ofbismuth compounds. To obtain theoretical expression for the thermoelectricproperties in a magnetic field of anisotropic materials, numerical analysis isbased on the solution of the classical Boltzmann equation expressed by tensors.The effective mass tensor of bismuth reported by some papers and relaxationtime approximation with three independent time constants are utilized in thisstudy. The magnetic field dependences of Seebeck coefficient tensor andconductivity tensor are calculated in various directions of temperaturegradient and magnetic field. The thermoelectric properties of bismuth undermagnetic field are calculated varying carrier concentration and relaxation timeor mobility. The optimum thermoelectric properties in magnetic field will bediscussed.