Altermagnetism and Room-Temperature Metal-to-Insulator Transition in CsCr 2 S 2 O

arXiv:2604.02114 · cond-mat.mtrl-sci, cond-mat.str-el · Submitted 2026-04-02 · Read on arXiv

cond-mat.mtrl-sci, cond-mat.str-el

Submitted: 2026-04-02

Updated: 2026-04-02

Comments: 20 pages, 12 figures, 2 tables

Journal ref: Journal of the American Chemical Society 2026

DOI: 10.1021/jacs.6c17601

License: http://creativecommons.org/licenses/by/4.0/

The gist: Metal-to-insulator transitions (MITs), particularly near room temperature, have been extensively studied in nonmagnetic and conventional ferromagnetic and antiferromagnetic systems, yet the

Terminology

Abstract

Metal-to-insulator transitions (MITs), particularly near room temperature, have been extensively studied in nonmagnetic and conventional ferromagnetic and antiferromagnetic systems, yet the co-emergence of MIT and altermagnetism (AM) remains unexplored. Here, a layered chromium-based compound CsCr 2 S 2 O that realizes this coexistence was synthesized. It crystalizes in CeCr 2 Si 2 C-type structure with Cr moments orders in a C-type antiferromagnetic configuration below T N = 326 K, constituting a room-temperature d-wave altermagnet. In the altermagnetic state, a subsequent Verwey-type MIT appears at T MI = 305 K, driven by a tetragonal-to-orthorhombic structural distortion and stripe charge ordering of Cr+2 /Cr+3 ions, while maintaining its altermagnetic character. First-principles calculations show moment-dependent spin-split electronic structures with maximum splitting energies of 0.6 eV and 0.3 eV in the metallic and insulating states, respectively. Our work links the two prominent phenomena, MIT and AM, in a single material, establishing a new platform for potential spintronic applications.

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