Charge Density Wave and Ferromagnetism in Intercalated CrSBr

TL;DR

This study demonstrates that intercalating CrSBr induces a high-temperature charge density wave and enhances ferromagnetism, revealing a coupling of charge and spin in a tunable, layered quantum material.

Contribution

It introduces a chemically intercalated CrSBr compound exhibiting room-temperature charge density waves and increased magnetic ordering, highlighting the interplay of charge and spin in a magnetic 2D material.

Findings

Induced charge density wave with onset above room temperature.

Increased magnetic ordering temperature from 132 K to 200 K.

Switch from antiferromagnetic to ferromagnetic interlayer coupling.

Abstract

In materials with one-dimensional electronic bands, electron-electron interactions can produce intriguing quantum phenomena, including spin-charge separation and charge density waves (CDW). Most of these systems, however, are non-magnetic, motivating a search for anisotropic materials where the coupling of charge and spin may affect emergent quantum states. Here, chemical intercalation of the van der Waals magnetic semiconductor CrSBr yields $Li_{0.17(2)} (tetrahydrofuran)_{0.26(3)} CrSBr$, which possess an electronically driven quasi-1D CDW with an onset temperature above room temperature. Concurrently, electron doping increases the magnetic ordering temperature from 132 K to 200 K and switches its interlayer magnetic coupling from antiferromagnetic to ferromagnetic. The spin-polarized nature of the anisotropic bands that give rise to this CDW enforces an intrinsic coupling of charge and spin. The coexistence and interplay of ferromagnetism and charge modulation in this exfoliatable material provides a promising platform for studying tunable quantum phenomena across a range of temperatures and thicknesses.