Orbital magnetic susceptibility and de Haas-van Alphen effect of a flat band from quantum geometry
The paper investigates how a magnetic field modifies flat bands, leading to purely geometric orbital susceptibility and a new Lifshitz–Kosevich formula for de Haas–van Alphen oscillations. It shows that the magnetization is determined by wavefunction geometry, and the oscillatory phase includes a second-order geometric term related to the field.