Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Poster Session: Correlated Electrons 2

TT 20.5: Poster

Montag, 20. März 2017, 15:00–19:00, P2-OG1

Field Control of Magnonic Heat Flow — •Benjamin Köhler and Wolfram Brenig — Institute for Theoretical Physics, Technische Universität 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 either external magnetic or electric fields. These fields are used to manipulated the heat flow, due to spin canting for the former and due to coupling to an additional Dzyaloshinsky-Moriya interaction for the latter. Using nonlinear spin wave theory and a Kubo approach we evaluate the thermal conductivity taking into account current relaxation by extrinsic mechanisms, as well as intrinsic magnon decay for finite magnetic fields. 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.