Drastic enhancement of the superconducting temperature in type-II Weyl semimetal candidate MoTe${}_2$ via biaxial strain

Abstract

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.

6 pages, 4 figures. Reference list updated. APL Materials (in press)

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Cited by in corpus (2)

• Shubnikov-de Haas oscillations of biaxial-strain-tuned superconductors in pulsed magnetic field up to 60 T
• Suppression of both superconductivity and structural transition in hole-doped MoTe${}_2$ induced by Ta substitution