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

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 non-magnetic layers whose structure is invariant under the P-421m 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 (ASSLIM) 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.

arXiv commentAccepted for publication in Physical Review X

References in corpus (24)

• A Field Guide to Spin Liquids
• Corner Transfer Matrix Renormalization Group Method
• Simulation of two dimensional quantum systems on an infinite lattice revisited: corner transfer matrix for tensor contraction
• Magnetic Superstructure in the Two-Dimensional Quantum Antiferromagnet SrCu2(BO3)2
• Frustrated quantum rare-earth pyrochlores
• Magnetization of SrCu2(BO3)2 in ultrahigh magnetic fields up to 118 T
• Crystals of bound states in the magnetization plateaus of the Shastry-Sutherland model
• Magnetostriction and magnetic texture to 97.4 Tesla in frustrated SrCu2(BO3)2
• A quantum magnetic analogue to the critical point of water
• PyCrystalField: Software for Calculation, Analysis, and Fitting of Crystal Electric Field Hamiltonians
• Theory of magnetization plateaux in the Shastry-Sutherland model
• Incomplete devil's staircase in the magnetization curve of SrCu2(BO3)2
• Ground States of the Ising Model on the Shastry-Sutherland Lattice and the Origin of the Fractional Magnetization Plateaus in Rare-Earth Tetraborides
• How quantum are classical spin ices?
• Phases and magnetization process of an anisotropic Shastry-Sutherland model
• Finding and proving the exact ground state of a generalized Ising model by convex optimization and MAX-SAT
• Magnetic properties of the Shastry-Sutherland lattice material BaNd${}_2$ZnO${}_5$
• Finite-temperature phase transition to $m=1/2$ plateau phase in a S=1/2 XXZ model on Shastry-Sutherland Lattices
• Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS
• Solving frustrated Ising models using tensor networks
• Field-Induced Partial Disorder in a Shastry-Sutherland Lattice
• A Candidate for the Quantum Spin Liquid Ground-State in the Shastry-Sutherland Lattice Material Yb${}_2$Be${}_2$GeO${}_7$
• Systematic Analysis of Crystalline Phases in Bosonic Lattice Models with Algebraically Decaying Density-Density Interactions
• Quantum phases of hardcore bosons with repulsive dipolar density-density interactions on two-dimensional lattices

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