Giant enhancement of superconductivity in few layers MoTe2**Project supported by the Guangdong Innovative and Entrepreneurial Research Team Program, China (Grant No. 2016ZT06D348), the National Natural Science Foundation of China (Grant No. 11874193), and the Shenzhen Fundamental Subject Research Program, China (Grant Nos. JCYJ20170817110751776 and JCYJ20170307105434022).

Abstract

Recently, the layered transition metal dichalcogenide 1T′ MoTe2 has attracted considerable attention due to its non-saturating magnetoresistance, type-II Weyl semimetal properties, superconductivity, and potential candidate for two-dimensional (2D) topological insulator in the single- and few-layer limit. Here in this work, we perform systematic transport measurements on thin flakes of MoTe2 prepared by mechanical exfoliation. We find that MoTe2 flakes are superconducting and have an onset superconducting transition temperature Tc up to 5.3 K, which significantly exceeds that of its bulk counterpart. The in-plane upper critical field (Hc2||) is much higher than the Pauli paramagnetic limit, implying that the MoTe2 flakes have Zeeman-protected Ising superconductivity. Furthermore, the Tc and Hc2 can be tuned by up to 320 mK and 400 mT by applying a gate voltage. Our result indicates that MoTe2 flake is a good candidate for studying exotic superconductivity with nontrivial topological properties.