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TT: Fachverband Tiefe Temperaturen
TT 9: Focus Session: Anomalous Quantum Oscillations
TT 9.3: Invited Talk
Monday, March 18, 2024, 16:00–16:30, H 0104
Quantum Oscillations of the Quasiparticle Lifetime in a Metal — •Nico Huber1, Valentin Leeb1,2, Andreas Bauer1,4, Georg Benka1, Johannes Knolle1,2,3, Christian Pfleiderer1,2,4, and Marc A. Wilde1,4 — 1Technical University of Munich (TUM) — 2MCQST, Munich — 3Blackett Laboratory, Imperial College London — 4TUM Zentrum für QuantumEngineering (ZQE), Munich
The low-lying excitations of metals are remarkably well explained by effective single-particle theories. Yet, strong interactions are abundant in condensed matter systems. This raises the question for direct spectroscopic signatures of phenomena beyond effective single-particle behavior. Here, we report on such a signature in the quantum oscillations (QOs) of the topological semimetal CoSi [1]. Its surprisingly simple QO spectrum related to Fermi surface pockets around the R-point [2,3] allows us to identify a QO frequency which defies the standard description in two ways. First, the frequency corresponds to the difference of quasi-particle (QP) orbits of two bands although the composite orbit is semi-classically forbidden. Second, the oscillations exist up to 50 K - in contrast to its constituent frequencies, which already vanish above a few K. We show that our findings are in excellent agreement with QOs of the QP lifetime [4]. Since the only precondition for this effect is a non-linear coupling of two orbits, e.g., due to QP scattering on defects, such QOs of the QP lifetime are generic for any metal featuring Landau quantization.
[1] Huber et al., Nature 621, 276 (2023)
[2] Huber et al., PRL 129, 026401 (2022)
[3] Guo et al., Nat. Phys. 18, 813 (2022)
[4] Leeb, Knolle, PRB 108, 054202 (2023)
Keywords: Quantum oscillations; Quasiparticle lifetime; Shubnikov-de Haas effect; CoSi