Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 75: Low Dimensional Systems
TT 75.7: Vortrag
Donnerstag, 21. März 2024, 16:45–17:00, H 3007
Tuneable band topology and non-reciprocal response in 2D altermagnets — •Peng Rao1, Alexander Mook2, and Johannes Knolle1,3,4 — 1Department of Physics, Technische Universität München, Garching, Germany — 2Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany — 3Blackett Laboratory, Imperial College London, London, United Kingdom — 4Munich Center for Quantum Science and Technology (MCQST), Munich, Germany
Non-reciprocal response due to time-reversal-symmetry (TRS) breaking in condensed matter platforms is an active field of research with broad theoretical and experimental interests, due to its application in building electrical devices, i.e. quantum circulators. In this work, we study the optical response of a newly proposed class of TRS-breaking materials called ’altermagnets’, where TRS is broken by collinear antiferromagnetic order. Unlike usual antiferromagnets, in an altermagnetic metal (i.e. RuO2) the spin-polarized Fermi surfaces are split by the order of the Fermi energy, exhibiting strong TRS breaking in its electronic properties. We first consider the altermagnet bandstructure and band topology using a 2D band Hamiltonian with spin-orbit coupling and magnetic field. We then investigate the non-reciprocal optical response by computing the optical conductivity tensor and anomalous Hall response. In particular, we estimate the Faraday angle using parameters that are quantitatively correct for RuO2.
Keywords: Altermagnetism; Anomalous Hall effect; Band topology; Non-reciprocal response; Faraday effect