Enhancements of the 3/2 and 5/2 frequencies of de Haas-van Alphen oscillations near the Lifshitz transition in the two-dimensional compensated metal with overtilted Dirac cones

Abstract

We study the de Haas-van Alphen (dHvA) oscillations in the two-dimensional compensated metal with overtilted Dirac cones near the Lifshitz transition. We employ the tight-binding model of $\alpha$-(BEDT-TTF)$_2$I$_3$, in which the massless Dirac fermions are realized. When a uniaxial pressure $(P)$ along the $y$-axis is applied above $P\simeq 0.2$ kbar in $\alpha$-(BEDT-TTF)$_2$I$_3$, one electron pocket, which encloses the overtilted Dirac points, is changed to two electron pockets, i.e., Lifshitz transition happens, while a hole pocket does not change a topology. We show that the Fourier components corresponding to the $3/2$ and $5/2$ areas of the hole pocket are anomalously enhanced in the region of pressure where the Lifshitz transition occurs. This phenomenon will be observed in the two-dimensional overtilted Dirac fermions near the Lifshitz transition.