Structures, charge density wave, and superconductivity of noncentrosymmetric 4Ha−NbSe2

Here, the authors report the charge density wave and superconductivity of noncentrosymmetric 4${H}_{a}$-NbSe${}_{2}$. In particular, it exhibits a large upper critical field ${H}_{c2}$(0) well beyond the Pauli paramagnetic limit. ${H}_{c2}$($T$) could be described by a two-band scenario that is also revealed via lower critical field and specific heat. The high ${H}_{c2}$ is expected to motivate the search of high-field superconductors in noncentrosymmetric materials.