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arXiv · 2104.08887

Quantum Criticality and Spin Liquid Phase in the Shastry-Sutherland model

Jianwei Yang·Anders W. Sandvik·Ling Wang
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Abstract

Using the density-matrix renormalization group method for the ground state and excitations of the Shastry- Sutherland spin model, we demonstrate the existence of a narrow quantum spin liquid phase between the previously known plaquette-singlet and antiferromagnetic states. Our conclusions are based on finite-size scaling of excited level crossings and order parameters. Together with previous results on candidate models for deconfined quantum criticality and spin liquid phases, our results point to a unified quantum phase diagram where the deconfined quantum-critical point separates a line of first-order transitions and a gapless spin liquid phase. The frustrated Shastry-Sutherland model is close to the critical point but slightly inside the spin liquid phase, while previously studied unfrustrated models cross the first-order line. We also argue that recent heat capacity measurements in SrCu2(BO3)2 show evidence of the proposed spin liquid at pressures between 2.6 and 3 GPa.

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Jianwei Yang, Anders W. Sandvik, Ling Wang. 2021-04-18. Quantum Criticality and Spin Liquid Phase in the Shastry-Sutherland model. https://doi.org/10.1103/physrevb.105.l060409

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