Pressure-driven dome-shaped superconductivity and electronic structural evolution in tungsten ditelluride.

Xing-Chen Pan,Li Pi,Xiangang Wan,Fei Yen,Zhongxia Wei,Yonghui Zhou,Baigeng Wang,Yanqing Feng,Huimei Liu,Zhaorong Yang,Xuliang Chen,Fengqi Song,Guanghou Wang,Yuheng Zhang,Zhenhua Chi

doi:10.1038/ncomms8805

Abstract

Tungsten ditelluride has attracted intense research interest due to the recent discovery of its large unsaturated magnetoresistance up to 60 T. Motivated by the presence of a small, sensitive Fermi surface of 5d electronic orbitals, we boost the electronic properties by applying a high pressure, and introduce superconductivity successfully. Superconductivity sharply appears at a pressure of 2.5 GPa, rapidly reaching a maximum critical temperature (Tc) of 7 K at around 16.8 GPa, followed by a monotonic decrease in Tc with increasing pressure, thereby exhibiting the typical dome-shaped superconducting phase. From theoretical calculations, we interpret the low-pressure region of the superconducting dome to an enrichment of the density of states at the Fermi level and attribute the high-pressure decrease in Tc to possible structural instability. Thus, tungsten ditelluride may provide a new platform for our understanding of superconductivity phenomena in transition metal dichalcogenides.

Highlights

Tungsten ditelluride has attracted intense research interest due to the recent discovery of its large unsaturated magnetoresistance up to 60 T
The W atoms form zigzag chains along the a axis resulting in a one-dimensional substructure within a 2D material[1]
The large MR is attributed to the perfect compensation between the opposite carriers, where the balance is too delicate to survive the intense pressures used in our experiments

Summary

Introduction

Tungsten ditelluride has attracted intense research interest due to the recent discovery of its large unsaturated magnetoresistance up to 60 T. We interpret the low-pressure region of the superconducting dome to an enrichment of the density of states at the Fermi level and attribute the high-pressure decrease in Tc to possible structural instability. An extremely large positive magnetoresistance (MR) was discovered at low temperatures in non-magnetic tungsten ditelluride (WTe2) TMD1. In the case of WTe2, the Te-5p and W-5d orbitals are spatially extended, making it very sensitive to variations caused by external pressure and strain This property could shed some light on the high-pressure induction of superconducting transport in WTe2. We observe the pressure-induced superconductivity, which exhibits a critical temperature (Tc) of 7 K at the pressure of 16.8 GPa. A dome-shaped Tc–P phase diagram is demonstrated.

Methods

Results

Conclusion