Accessing new magnetic regimes by tuning the ligand spin-orbit coupling in van der Waals magnets

• Published in: Science advances Vol. 6; no. 30; p. eabb9379
• Main Authors: Tartaglia, Thomas A, Tang, Joseph N, Lado, Jose L, Bahrami, Faranak, Abramchuk, Mykola, McCandless, Gregory T, Doyle, Meaghan C, Burch, Kenneth S, Ran, Ying, Chan, Julia Y, Tafti, Fazel
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science (AAAS) 24.07.2020; American Association for the Advancement of Science
• Subjects: Chemistry; Condensed Matter Physics; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.abb9379

Van der Waals (VdW) materials have opened new directions in the study of low dimensional magnetism. A largely unexplored arena is the intrinsic tuning of VdW magnets toward new ground states. Chromium trihalides provided the first such example with a change of interlayer magnetic coupling emerging upon exfoliation. Here, we take a different approach to engineer previously unknown ground states, not by exfoliation, but by tuning the spin-orbit coupling (SOC) of the nonmagnetic ligand atoms (Cl, Br, I). We synthesize a three-halide series, CrCl Br I , and map their magnetic properties as a function of Cl, Br, and I content. The resulting triangular phase diagrams unveil a frustrated regime near CrCl . First-principles calculations confirm that the frustration is driven by a competition between the chromium and halide SOCs. Furthermore, we reveal a field-induced change of interlayer coupling in the bulk of CrCl Br I crystals at the same field as in the exfoliation experiments.