Regensburg 2022 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 8: Frustrated Magnets – Strong Spin-Orbit Coupling

TT 8.3: Talk

Monday, September 5, 2022, 17:45–18:00, H10

Quantum Monte Carlo simulations of generalized Kitaev models: applications to α-RuCl₃ — •Toshihiro Sato¹ and Fakher F. Assaad^1,2 — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — ²Würzburg-Dresden Cluster of Excellence ct.qmat, Germany

We introduce a phase pinning approach in the realm of the auxiliary field quantum Monte Carlo (QMC) algorithm that mitigates the severity of the negative sign problem inherent to QMC methods of frustrated spin systems [1]. This allows us to access high-temperature thermodynamic and dynamical properties of the aforementioned systems and, for instance, carry out exact QMC simulations in a window of temperatures relevant to experiments for various frustrated magnets. We use our method to carry out extensive simulations of thermodynamic properties under magnetic fields in generalized Kitaev models describing α-RuCl₃, and discuss the characteristic feature in the field-direction dependence of the magnetic susceptibility, the specific heat as well as the magnetotropic coefficient. Our numerical results allow for direct comparison with recent measurements of the magnetotropic coefficient in α-RuCl₃ [2].

[1] T. Sato and F. F. Assaad, Phys. Rev. B. 104, L081106 (2021)

[2] K. A. Modic et al., Nat. Phys. (2020)