Theory of Difference Frequency Quantum Oscillations

Microstructured Quantum Matter Seminar

  • Datum: 30.11.2022
  • Uhrzeit: 15:00 - 16:00
  • Vortragender: Valentin Leeb
  • TU Munich
  • Ort: CFEL (Bldg. 99)
  • Raum: Seminar Room II, EG.078
  • Gastgeber: Carsten Putzke

Quantum oscillations (QO) describe the periodic variation of physical observables as a function of inverse magnetic field in metals. The Onsager relation connects the basic QO frequencies with the extremal areas of closed Fermi surface pockets, and the theory of magnetic breakdown explains the observation of sums of QO frequencies at high magnetic fields. Here, we develop a quantitative theory of difference frequency QOs in metals with multiple Fermi pockets with parabolic or linearly dispersing excitations. We show that a non-linear interband coupling, e.g. in the form of interband impurity scattering, can give rise to otherwise forbidden QO frequencies which can persist up too much higher temperatures compared to the basis frequencies. Additionally, numerical simulations are consistent with our theory and can provide precise predictions for specific materials. We discuss the experimental implications of our findings for different materials.

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