Dresden 2020 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 46: Poster Session: Frustrated Magnets, Quantum Magnets, Charge Order and Complex Oxids

TT 46.18: Poster

Wednesday, March 18, 2020, 15:00–19:00, P2/2OG

Field Control of Magnonic Heat Flow — •Benjamin Köhler and Wolfram Brenig — Institute for Theoretical Physics, Technical University Braunschweig, Germany

Insulating quantum magnets allow for genuine spin transport phenomena without carrier dynamics. Controlling such transport by means of external fields is vital for potential device design. Here we study the thermal conductivity of a two-dimensional square lattice spin-1/2 Heisenberg antiferromagnet in the presence of a homogeneous magnetic and a spatially confined electric field. The former alters the Zeeman energy and the latter the Dzyaloshinskii-Moriya interaction. Both affect the spin-canting which controls the heat flow.

For the magnetic field, we use non-linear spin wave theory and a Kubo approach to evaluate the thermal conductivity taking into account current relaxation via intrinsic magnon decay for finite fields and temperature. We use a real-space approach to spin wave theory for the spatially confined electric field. Results for the heat conductivity as a function of the temperature, the strength of the external field, and shape of the electric-field gated region are presented. Semi-quantitative estimates for attainable variations of the heat conductivity in the context of spincaloric applications are included.