Short and long-range magnetic ordering and emergent topological transition in (Mn1−xNix)2P2S6

Abstract Two-dimensional magnetic materials with tunable physical parameters are emerging as potential candidates for topological phenomena as well as applications in spintronics. The famous Mermin-Wagner theorem states that spontaneous spin symmetry cannot be broken at finite temperature in low dim...

Full description

Saved in:
Bibliographic Details
Main Authors: Nasaru Khan, Deepu Kumar, Shantanu Semwal, Yuliia Shemerliuk, Bernd Büchner, Koushik Pal, Saicharan Aswartham, Pradeep Kumar
Format: Article
Language:English
Published: Nature Portfolio 2025-02-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-88586-0
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Two-dimensional magnetic materials with tunable physical parameters are emerging as potential candidates for topological phenomena as well as applications in spintronics. The famous Mermin-Wagner theorem states that spontaneous spin symmetry cannot be broken at finite temperature in low dimensional magnetic systems which forbids the possibility of a transition to a long-range ordered state in a two-dimensional magnetic system at finite temperature. Though, there are some exceptions to Mermin-Wagner theorem in particular low dimensional magnetic systems with topologically ordered phase transitions. Here, we present an in-depth temperature dependent analysis for the bulk single crystals of two-dimensional (Mn1−xNix)2P2S6 with x = 1, 0.7, 0.3, 0 using the Raman spectroscopy supported by first-principles calculations of the phonon frequencies. We observed multiple phase transitions with tunability as a function of doping associated with the short and long-range spin-spin correlations. First transition at ~ 150 K to ~ 170 K for x = 0 to x = 0.7, and second one from ~ 60 K to ~ 153 K. Quite interestingly, a third transition is observed at low temperature (much below their respective T N ) ~ 24 K to ~ 60 K and is attributed to the potential topological phase transition. These transitions are marked by the distinct changes observed in the temperature evolution of the phonon self-energy parameters, modes intensity and dynamic Raman susceptibility.
ISSN:2045-2322