Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 7: Fluctuations, Noise, Magnetotransport, and Related Topics
TT 7.1: Vortrag
Montag, 5. September 2022, 15:00–15:15, H23
Large Hall and Nernst effect from chiral spin fluctuations — Kamil K. Kolincio1, Max Hirschberger2,3, and •Jan Masell3,4 — 1Gdansk Tech, Gdansk, Poland — 2University of Tokyo, Tokyo, Japan — 3RIKEN CEMS, Wako, Japan — 4Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
Magnetic materials with tilted electron spins exhibit conducting behaviour that is explained by the geometrical Berry phase, driven by a chiral (left- or right-handed) spin-habit. Dynamical and nearly random spin fluctuations, with a slight trent towards left- or right-handed chirality, represent a promising route to realizing Berry-phase phenomena at elevated temperatures. [1] Here, we report thermoelectric and electric transport experiments on a triangular and on a slightly distorted kagomé lattice material, respectively. We show that the impact of chiral spin fluctuations is strongly enhanced for the kagomé lattice. Our modelling shows that the geometry of the kagomé lattice plays a crucial role as it helps to avoid cancellation of Berry-phase contributions already in the disordered (paramagnetic) state. Hence, the observations for the kagomé material contrast with theoretical models treating magnetization as a continuous field, and emphasize the role of lattice geometry on emergent electrodynamic phenomena.
[1] K. K. Kolincio, M. Hirschberger, J. Masell, S. Gao, A. Kikkawa, Y. Taguchi, T.-h. Arima, N. Nagaosa, Y. Tokura, PNAS 118, e2023588118 (2021)
[2] K. K. Kolincio et al., submitted