Electrical Properties of a Quasi-One-Dimensional Nb3Te4 Single Crystal

Abstract

The electrical resistance and thermoelectric power of Nb₃Te₄ were measured along the quasi-one-dimensional c-axis. Below about 100 K, the resistivity follows the form T^2.2, suggesting the electron-electron Umklapp process for charge carrier scattering. Around 38 K, there is a resistivity swelling which would be related to the charge-density-wave phase transition. Anomalies in the thermopower are observed below 150 K. The transition temperature to superconductivity is 2.3 K, and the upper critical magnetic field for type-II superconductivity versus temperature is linear in the temperature range 2.3∼2.0 K. The coherence lengths at 0 K parallel and perpendicular to the c-axis are estimated as 750 Å and 69 Å, respectively. The effective mass ratio perpendicular and parallel to the c-axis at 2.0 K is 115±10, which indicates that this material is strongly anisotropic.