Emergent superconductivity in two-dimensional <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>NiTe</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> crystals
Feipeng Zheng, Xi‐Bo Li, Peng Tan, Yiping Lin, Lingxiao Xiong, Xiaobo Chen, Ji Feng
Abstract
Two-dimensional superconductors exfoliated from layered materials harbor novel superconductivity and exotic correlated phases, often concomitantly, but their discovery has been few and far between. Employing the anisotropic Migdal-Eliashberg formalism based on ab initio calculations, we find monolayer ${\mathrm{NiTe}}_{2}$ to be an intrinsic superconductor with a ${T}_{\text{c}}\ensuremath{\sim}5.7$ K, although the bulk crystal is not known to superconduct. Remarkably, bilayer ${\mathrm{NiTe}}_{2}$ intercalated with lithium is found to display two-gap superconductivity with a critical temperature ${T}_{\text{c}}\ensuremath{\sim}11.3$ K and a superconducting gap of $\ensuremath{\sim}3.1$ meV, arising from a synergy of electronic and phononic effects. As monolayer and bilayer ${\mathrm{NiTe}}_{2}$ have been recently isolated experimentally, and lithium can be inserted into the bilayer via ionic liquid gating, the comparatively high ${T}_{\text{c}}$, substrate independence, and proximity tunability will make these superconductors ideal platforms for exploring intriguing correlation effects and quantum criticality associated two-dimensional superconductivity.