Geometric orbital susceptibility: Quantum metric without Berry curvature

Article

关键词: BLOCH ELECTRONS;    MAGNETIC-SUSCEPTIBILITY;    CONDUCTION ELECTRONS;    FLAT BANDS;    DIAMAGNETISM;    FERROMAGNETISM;    LATTICE;    METALS;    STATES;    FIELD;   

DOI  :  10.1103/PhysRevB.94.134423

来源: SCIE

【 摘 要 】

The orbital magnetic susceptibility of an electron gas in a periodic potential depends not only on the zero field energy spectrum but also on the geometric structure of cell-periodic Bloch states which encodes interband effects. In addition to the Berry curvature, we explicitly relate the orbital susceptibility of two-band models to a quantum metric tensor defining a distance in Hilbert space. Within a simple tight-binding model allowing for a tunable Bloch geometry, we show that interband effects are essential even in the absence of Berry curvature. We also show that for a flat band model, the quantum metric gives rise to a very strong orbital paramagnetism.

【 授权许可】

Free