Drastic enhancement of the superconducting temperature in type-II Weyl semimetal candidate MoTe\(_2\) via biaxial strain

Type-II Weyl semimetal candidate MoTe\(_2\), which superconducts at T_c~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 MoTe\(_2\) to biaxial strain. With this approach, we successfully enhance the \(T_c\) of MoTe\(_2\) five-fold 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 MoTe\(_2\), 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 MoTe\(_2\). Our work shows that biaxial strain is an effective knob to tune the electronic properties of MoTe\(_2\). Due to the simplicity of our methodology to apply biaxial strain, we anticipate its direct applicability to a wider class of quantum materials.