SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 23: Kagome Systems

TT 23.11: Vortrag

Dienstag, 28. März 2023, 12:15–12:30, HSZ 304

Classical and quantum frustrated models of planar X-Y spins on the Kagome lattice: anisotropic magnetic patterns — •Oliver Neyenhuys, Mikhail Fistul, and Ilya Eremin — Ruhr Universität Bochum

We present a theoretical study of various highly anisotropic magnetic patterns occurring in the geometrically frustrated model of planar X-Y spins on the Kagome two-dimensional lattice. Frustration is introduced by a specific spatial arrangement of both ferromagnetic and anti-ferromagnetic bonds between adjacent magnetic moments on the lattice vertices. At the critical value of frustration f = 3/4 such a system displays the phase transition from an ordered ferromagnetic state to frustrated regime featuring a highly degenerate ground state in which topological (anti)vortices penetrate each cell. Taking into account a generous amount of topological constraints, the thermal fluctuations and the quantum tunneling induced transitions between these vortices/anti-vortices, we derive an effective Ising spin Hamiltonian on the corresponding hexagonal lattice, in which a strong long-range interaction between a well separated (anti)vortices occurs. By making use of the mean field analysis and direct numerical diagonalization of the Hamiltonian we characterize various classical and quantum phases and phase transitions between them for large and small Kagome lattices. Experimental observation of such magnetic patterns with coherent networks of superconducting qubits will be discussed.