Observation of Unprecedented Fractional Magnetization Plateaus in a New Shastry-Sutherland Ising Compound

Yadav L, Rufino A, Bag R, Ennis M, Koziol J, Cruz CD, Kolesnikov AI, Garlea VO, Taddei KM, Graf D, Schmidt KP, Mila F, Haravifard S (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Physical Review X American Physical Society

Book Volume: 15

Article Number: 041045

Journal Issue: 4

DOI: 10.1103/9ynf-xx1t

Abstract

Geometrically frustrated magnetic systems, such as those based on the Shastry-Sutherland lattice (SSL), offer a rich playground for exploring unconventional magnetic states. The delicate balance between competing interactions in these systems leads to the emergence of novel phases. We present the characterization of Er2Be2GeO7, an SSL compound with Er3+ ions forming orthogonal dimers separated by nonmagnetic layers whose structure is invariant under the P4¯21m space group. Neutron scattering reveals an antiferromagnetic dimer structure at zero field, typical of Ising spins on that lattice and consistent with the anisotropic magnetization observed. However, magnetization measurements exhibit fractional plateaus at 1/4 and 1/2 of saturation, in contrast to the expected 1/3 plateau of the SSL Ising model. By comparing the energy of candidate states with ground-state lower bounds we show that this behavior requires spatially anisotropic interactions, leading to an anisotropic Shastry-Sutherland Ising model symmetric under the Cmm2 space group. This anisotropy is consistent with the small orthorhombic distortion observed with single-crystal neutron diffraction. The other properties, including thermodynamics, which have been investigated theoretically using tensor networks, point to small residual interactions, potentially due to further couplings and quantum fluctuations. This study highlights Er2Be2GeO7 as a promising platform for investigating exotic magnetic phenomena.

Authors with CRIS profile

Jan Koziol Lehrstuhl für Theoretische Physik Kai Phillip Schmidt Professur für Theoretische Physik

Involved external institutions

Oak Ridge National Laboratory US United States (USA) (US) National High Magnetic Field Laboratory (MagLab) US United States (USA) (US) Duke University US United States (USA) (US) École Polytechnique Fédérale de Lausanne (EPFL) CH Switzerland (CH)

How to cite

APA:

Yadav, L., Rufino, A., Bag, R., Ennis, M., Koziol, J., Cruz, C.D.,... Haravifard, S. (2025). Observation of Unprecedented Fractional Magnetization Plateaus in a New Shastry-Sutherland Ising Compound. Physical Review X, 15(4). https://doi.org/10.1103/9ynf-xx1t

MLA:

Yadav, Lalit, et al. "Observation of Unprecedented Fractional Magnetization Plateaus in a New Shastry-Sutherland Ising Compound." Physical Review X 15.4 (2025).

BibTeX: Download