Schematic diagram of evidences of superconductivity. (Imaged by CHEN Xuliang)

Most recently, an extremely large positive magnetoresistance (MR) was discovered at low temperatures in non-magnetic tungsten ditelluride (WTe2). In contrast to other materials, the MR of WTe2 remains unsaturated even at extremely high applied magnetic fields of 60 T. It has been observed that at low temperatures the hole and electron pockets are approximately the same size, and that disruption in the balance between the two results in strong suppression of the MR. A perfect balance between the electron and hole populations may therefore be the primary source of these novel and unwavering MR effects. As a semimetal, the density of states at the Fermi level (N(EF)) is rather low, and no superconductivity has ever been detected down to 0.3 K.

High pressure has been shown to be a clean and powerful means of generating novel physical states, having been particularly effective not only in tuning the TC of the superconductivity in elements and compounds but also in inducing superconductivity with ferromagnetic or antiferromagnetic orders as their ground states at ambient pressure. Moreover, in the case of WTe2, the Te-5p and W-5d orbitals are spatially extended, thus 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.

Recently, three research groups led by Prof. YANG Zhaorong from Institute of Solid State Physics, Chinese Academy of Sciences, Prof. SONG Fengqi and Prof. WAN Xiangang from Nanjing University investigated the physics in WTe2 under high pressure using diamond anvil cells (DAC). They observed 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. This study was published online at Nature Communications, entitled Pressure-driven dome-shaped superconductivity and electronic structural evolution in tungsten ditelluride.

This work was sponsored by the National Key Basic Research Program of China (Grant No. 2011CBA00111) and the Natural Science Foundation of China (Grant No. U1332143).

Contact:

Prof. YANG Zhaorong, Ph. D, Principal Investigator

Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences

350 Shushanhu Rd, Hefei, Anhui 230031, China

Tel: 86-551-6559-3523

E-mail: zryang@issp.ac.cn