Extra Seminar - Würzburg ToCoTronics Colloquium

In a series of papers [1,2,3,4], we have developed a kinetic theory for weakly disordered multi-band Hamiltonian electron systems. The theory is based on a systematic ħ-expansion and, while recovering the semiclassical transport theory at lowest order, is able to include the effects of quantum geometry in the next order. By using a gradient-Moyal product and the Wilson-line technique, the resulting kinetic equations are manifestly gauge-invariant. In this talk, after a brief presentation of the theory, a number of applications are discussed in the context of spintronics. In particular, I will report on a recent calculation about the orbital angular momentum accumulation observed in metallic systems.

[1] Valet and Raimondi, EPL 143, 26004 (2023) https://doi.org/10.1209/0295-5075/ace379
[2] Valet and Raimondi,  Physical Review B 111, L041118 (2025) https://doi.org/10.1103/PhysRevB.111.L041118 
[3] Raimondi and Valet, Condensed Matter 10, 4 (2025) https://doi.org/10.3390/condmat10010004
[4] Valet, Jaffrès, Cros and Raimondi, arXiv:2507.06771 - accepted in PRL (2025) https://doi.org/10.1103/86cm-yn9z