Version 2 2024-03-18, 15:35Version 2 2024-03-18, 15:35
Version 1 2024-03-15, 11:49Version 1 2024-03-15, 11:49
journal contribution
posted on 2024-03-18, 15:35authored byMingzhang Yang, Tianping Ying, Jian-gang Guo
Understanding how matter changes under high pressure
provides valuable
insights into predicting the evolution of crystal structures and their
associated physical properties. In layered SnAs-based compounds under
pressure, such as Li0.6Sn2As2 and
NaSnAs, a two-dimensional (2D) topotactic transition from trigonal
SnAs3 to square SnAs4 has been proposed and
verified, which leads to the better alignment of p-orbitals and enhanced superconductivity. In this study, we report
a novel three-dimensional (3D) topotactic transition occurring in
layered Sn4As3, in which a steric hindrance
As layer is located between two adjacent SnAs3 layers.
This structural transition from 2D to 3D can be understood as a stereochemical
rearrangement of the transformed SnAs3–SnAs4 blocks. Due to the perfectly aligned p-orbitals
in the orthogonal bonds of the Pm3̅m phase that facilitate electron hopping, the superconducting
transition temperature (Tc) exceeds that
of Li0.6Sn2As2 and sets a record
among all reported SnAs-based compounds.