2023/03/03 by Andrew J. Cole, Alenna Streeter, Cole, Andrew +17
Chemistry · Engineering · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Atomic physics #Chemistry #Condensed matter physics #Degenerate energy levels #FOS: Physical sciences #Ground state #Halide #Inorganic chemistry #Materials Science (cond-mat.mtrl-sci) #Metal halides #Molecule #Perovskite Materials and Applications #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Strongly Correlated Electrons (cond-mat.str-el) #van der Waals force
paper · pdf · doi:10.48550/arxiv.2303.02238
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2023/03/03 · openalex created_date 2023/03/09 · openalex updated_date 2026/07/28
Mixed halide chemistry has recently been utilized to tune the intrinsic magnetic properties of transition-metal halides - one of the largest families of magnetic van der Waals materials. Prior studies have shown that the strength of exchange interactions, hence the critical temperature, can be tuned smoothly with halide composition for a given ground-state. Here we show that the ground-state itself can be altered by a small change of halide composition leading to a quantum phase transition in FeCl3-xBrx. Specifically, we find a three-fold jump in the Néel temperature and a sign change in the Weiss temperature at x= 0.08 corresponding to only 3% bromine doping. Using neutron scattering, we reveal a change of the ground-state from spiral order in FeCl3 to A-type antiferromagnetic order in FeBr3. Using first-principles calculations, we show that a delicate balance between nearest and next-nearest neighbor interactions is responsible for such a transition. These results support the proximity of FeCl3 to a spiral spin liquid state, in which competing interactions and nearly degenerate magnetic k-vectors may cause large changes in response to small perturbations.