Preparation and basic physical properties of BiTeI single crystals

Abstract

A modified Bridgman method is described, which makes it possible to prepare homogeneous BiTeI crystals using excess iodine. At room temperature the values of the electrical conductivity of the crystals range around 2000 Ω⁻¹ cm⁻¹, the Hall constant value about 0·09 cm⁻³ coul⁻¹, the Seebeck coefficient about 50 μV K⁻¹. In connection with the assumption of super-stoichiometric iodine content we expect there exist point defects in the crystals, where Te atoms are replaced with I atoms, which gives rise to electric conductivity. On the basis of the temperature dependence of the electron mobility one can suppose a mixed mechanism of the scattering of the free carriers by the acoustic branch of lattice vibrations and by ionized impurities.