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MA: Fachverband Magnetismus
MA 21: Frustrated Magnets I
MA 21.10: Vortrag
Mittwoch, 19. März 2025, 12:00–12:15, H18
Dynamical response of the Kitaev quantum spin liquid in the KJΓ-model under external magnetic field — •Peng Rao1, Roderich Moessner2, and Johannes Knolle1,3,4 — 1Physics Department, Technical University of Munich, TUM School of Natural Sciences, 85748 Garching, Germany — 2Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany — 3Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 München, Germany — 4Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
We study the dynamical structure factor of the Kitaev quantum spin liquid (KQSL) generally, i.e. away from the solvable Kitaev limit, in the KJΓ-model with external magnetic field. Using Majorana mean field theory, we compute spin susceptibility by including Majorana interactions in the random phase approximation (RPA). At zero field for the pure Kitaev model, RPA reproduces qualitatively spin susceptibility in the adiabatic approximation, which is close to the exact result. Small non -Kitaev couplings J and Γ induce sharp low-energy magnon modes as Majorana bound states. Larger couplings or finite field generally tend to weaken the KQSL and cause the sharp modes to condense, whence the system becomes magnetically ordered. However in specific paramter regimes, magnetic field may destroy the zero-field magnetic order and stabilize KQSL at intermediate field values, thus exemplifying the proposed ‘field-induced KQSL’.
Keywords: Quantum spin liquid; Kitaev materials; Spin susceptibility