Drastic enhancement of the superconducting temperature in type-II Weyl semimetal candidate MoTe2 via biaxial strain

A type-II Weyl semimetal candidate MoTe2, which superconducts at T-c similar to 0.1 K, is one of the promising candidates for realizing topological superconductivity. However, the exceedingly low T-c is associated with a small upper critical field (H-c2), implying a fragile superconducting phase that only exists on a small region of the H-T phase diagram. Here, we describe a simple and versatile approach based on the differential thermal expansion between dissimilar materials to subject a thin single crystalline MoTe2 to biaxial strain. With this approach, we successfully enhance the T-c of MoTe2 by fivefold and consequently expand the superconducting region on the H-T phase diagram significantly. To demonstrate the relative ease of studying the superconductivity in the biaxially strained MoTe2, we further present the magnetotransport data, enabling the study of the temperature-dependent H-c2 and the anisotropy of the superconducting state, which would otherwise be difficult to obtain in a free-standing MoTe2. Our work shows that biaxial strain is an effective knob to tune the electronic properties of MoTe2. Due to the simplicity of our methodology to apply biaxial strain, we anticipate its direct applicability to a wider class of quantum materials.

Automated summary

Researchers applied biaxial strain on a thin single crystalline MoTe2 using the differential thermal expansion between dissimilar materials, successfully increasing its superconducting critical temperature by fivefold and expanding the superconducting region significantly. This simple and versatile approach can be used to tune the electronic properties of MoTe2 and other quantum materials.