Valence-skipping and quasi-two-dimensionality of superconductivity in a van der Waals insulator.

ABSTRACT: Valence fluctuation of interacting electrons plays a crucial role in emergent quantum phenomena in correlated electron systems. The theoretical rationale is that this effect can drive a band insulator into a superconductor through charge redistribution around the Fermi level. However, the root cause of such a fluctuating leap in the ionic valency remains elusive. Here, we demonstrate a valence-skipping-driven insulator-to-superconductor transition and realize quasi-two-dimensional superconductivity in a van der Waals insulator GeP under pressure. This is shown to result from valence skipping of the Ge cation, altering its average valency from 3+ to 4+, turning GeP from a layered compound to a three-dimensional covalent system with superconducting critical temperature reaching its maximum o

SUBMITTER: Zhang C 

PROVIDER: S-EPMC9663542 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature