Journal Article

Shubnikov–de Haas effect in the Falicov–Kimball model: strong correlation meets quantum oscillation

Luo, Hong-Gang, Zhong, Yin, Yang, Wei-Wei

2024

Overview

We present a comprehensive investigation of quantum oscillations (QOs) in the strongly-correlated Falicov-Kimball model (FKM). The FKM is a particularly suitable platform for probing the non-Fermi liquid (NFL) state devoid of quasiparticles, affording exact Monte Carlo simulation across all parameter spaces. In the high-correlation regime, we report the presence of prominent QOs in magnetoresistance and electron density at low temperatures within the phase separation state. The frequency behavior of these oscillations uncovers a transition in the Fermi surface as electron density diminishes, switching from hole-like to electron-like. Both types of Fermi surfaces are found to conform to the Onsager relation, establishing a connection between QOs frequency and Fermi surface area. Upon exploring the temperature dependence of QOs amplitude, we discern a strong alignment with the Lifshitz-Kosevich (LK) theory, provided the effective mass is suitably renormalized. Notwithstanding, the substantial enhancement of the overall effective mass results in a notable suppression of the QOs amplitude within the examined temperature scope, a finding inconsistent with Fermi liquid predictions. For the most part, the effective mass diminishes as the temperature increases, but an unusual increase is observed at the proximity of the second-order phase transition instigated by thermal effects. As the transition ensues, the regular QOs disappear, replaced by irregular ones in the NFL state under a high magnetic field. We also uncover significant QOs in the insulating charge density wave state under weak interactions ( 0 < U < 1 ), a phenomenon we elucidate through analytical calculations. Our findings shed light on the critical role of quasiparticles in the manifestation of QOs, enabling further understanding of their function in this context.

• Publisher: IOP Publishing
• Subject: Amplitudes / Charge density waves / Correlation / doped Mott insulator / Electron density / Elementary excitations / exactly solvable model / Fermi liquids / Fermi surfaces / Insulation / Low temperature / Magnetoresistance / Magnetoresistivity / Monte Carlo simulation / Oscillations / Phase separation / Phase transitions / quantum oscillation / Temperature / Temperature dependence / Temperature effects