The Superconductivity in GeTe Under High Pressure Effect

Cheng-Yen Liu^1*, Tsu-Lien Hung¹, Yang-Yuan Chen¹

¹Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Cheng-Yen Liu, email:tony8702205107@gmail.com

GeTe (Germanium Telluride) is generally regarded as a thermoelectric material, featuring a metallic behavior with superconducting transition temperature ~ 0.3 K at ambient pressure. While no research work has been carried out for its pressure effect on superconductivity to dates. In this work, the low temperature electrical resistivity is performed on GeTe by Van der Pawu method under high pressure in a diamond anvil cell. Superconductivity is observed to onset at P> 11 GPa with a critical transition temperature T_c ~ 3 K, the superconductivity is also confirmed with a characteristic of magnetic field suppression. With pressure increasing, the T_c is further increased to 5 K at 25 GPa. According to the previous structural analysis, three pressure-induced phase transitions are displayed in GeTe, i.e., a low-pressure rhombohedral phase (P< ~ 4G Pa), an intermediate pressure cubic phase (P= 4-15 GPa) and a high-pressure orthorhombic phase (P> ~ 15 GPa). Since the superconductivity starts to appear at P> 11 GPa during a mixed phase of cubic phase and orthorhombic phase, the phase transition may play an important role on the emergence of superconductivity. We expect T_c can be further enhanced to a higher temperature with a continuously increasing external pressure, and this has been planned in our future work.

Keywords: Superconductivity, High pressure, GeTe, Critical transition temperature