Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Quantum Magnets and Molecular Magnets (joint session TT/MA)

TT 6.9: Vortrag

Montag, 12. März 2018, 11:45–12:00, H 3010

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 thermal conductivity of a two dimensional square lattice spin-1/2 Heisenberg antiferromagnet in the presence of an external field. The latter is used to manipulated the heat flow due to spin canting.

Using nonlinear spin wave theory and a Kubo approach we evaluate the thermal conductivity taking into account current relaxation via intrinsic magnon decay for finite fields and temperature. Semi-quantitative estimates for attainable variations of the heat conductivity in realistic materials will be presented as a function of the temperature and the external fields, suggesting interesting implications for spin caloritronic applications.