Dresden 2020 – wissenschaftliches Programm
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TT 5.7: Vortrag
Montag, 16. März 2020, 11:00–11:15, HSZ 304
Low-temperature thermal conductivity in the frustrated spin chain mineral Linarite — •Matthias Gillig1, Xiaochen Hong1, Gaël Bastien1, Anja U.B. Wolter1, Bernd Büchner1, 2, and Christian Hess1, 2 — 1Leibniz-Institut für Festkörper- und Werkstoffforschung, Dresden, Germany — 2Center for Transport and Devices, TU Dresden, Germany
Motivated by recent theoretical results which predict a finite thermal Drude weight in frustrated spin chains, we have studied the thermal conductivity of the mineral Linarite PbCuSO4(OH)2 at low temperature. This well-studied material forms a monoclinic structure where a sequence of Cu(OH)2 units forms a S=1/2 spin chain. Competing FM nearest-neighbor and AFM next-nearest-neighbor interactions in this low dimensional spin structure create a magnetically frustrated system which orders below TN = 2.8 K in an elliptical spiral ground state. Upon applying magnetic field along the spin chain direction, other magnetically ordered phases can be induced. For fields of 10 T and higher the spin system is fully polarized. Our results reveal that the thermal conductivity κ in zero field is dominated by a phononic contribution. As a function of magnetic field κ shows a peculiar non-monotonic behavior. Whenever the magnetic field value approaches a critical field, κ is highly suppressed. This trend can be explained by strong magnetic fluctuations which are expected near a phase boundary and which reduce thermal conductivity by phonon scattering.