Orbital Dynamics in Centrosymmetric Systems

TL;DR

This paper explores the unique orbital dynamics in centrosymmetric systems, revealing phenomena distinct from spin dynamics and proposing methods for experimental differentiation.

Contribution

It demonstrates that orbital angular momentum exhibits unique behaviors unlike spin, and introduces a quantum Boltzmann approach to analyze these phenomena.

Findings

Orbital angular momentum can oscillate without symmetry breaking.

The quantum Boltzmann approach reproduces the orbital Hall effect.

Additional orbital dynamics phenomena are predicted and discussed.

Abstract

Orbital dynamics in time-reversal-symmetric centrosymmetric systems is examined theoretically. Contrary to common belief, we demonstrate that many aspects of orbital dynamics are qualitatively different from spin dynamics because the algebraic properties of the orbital and spin angular momentum operators are different. This difference generates interesting orbital responses, which do not have spin counterparts. For instance, the orbital angular momentum expectation values may oscillate even without breaking neither the time-reversal nor the inversion symmetry. Our quantum Boltzmann approach reproduces the previous result on the orbital Hall effect and reveals additional orbital dynamics phenomena, whose detection schemes are discussed briefly. Our work will be useful for the experimental differentiation of the orbital dynamics from the spin dynamics.