SciPost Phys. 4, 024 (2018) ·
published 13 May 2018
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· pdf
A generalized semiclassical quantization condition for cyclotron orbits was
recently proposed by Gao and Niu \cite{Gao}, that goes beyond the Onsager
relation \cite{Onsager}. In addition to the integrated density of states, it
formally involves magnetic response functions of all orders in the magnetic
field. In particular, up to second order, it requires the knowledge of the
spontaneous magnetization and the magnetic susceptibility, as was early
anticipated by Roth \cite{Roth}. We study three applications of this relation
focusing on two-dimensional electrons. First, we obtain magnetic response
functions from Landau levels. Second we obtain Landau levels from response
functions. Third we study magnetic oscillations in metals and propose a proper
way to analyze Landau plots (i.e. the oscillation index $n$ as a function of
the inverse magnetic field $1/B$) in order to extract quantities such as a
zero-field phase-shift. Whereas the frequency of $1/B$-oscillations depends on
the zero-field energy spectrum, the zero-field phase-shift depends on the
geometry of the cell-periodic Bloch states via two contributions: the Berry
phase and the average orbital magnetic moment on the Fermi surface. We also
quantify deviations from linearity in Landau plots (i.e. aperiodic magnetic
oscillations), as recently measured in surface states of three-dimensional
topological insulators and emphasized by Wright and McKenzie \cite{Wright}.
