Gauge-invariant formulation of spin-current density-functional theory
Gauge-invariant formulation of spin-current density-functional theory
Spin-currents and non-Abelian gauge potentials in electronic systems can be treated by spin-current density-functional theory, whose main input is the exchange-correlation (xc) energy expressed as a functional of spin-currents. Constructing a functional of spin-currents that is invariant under $\text{U}(1)\ifmmode\times\else\texttimes\fi{}\text{SU}(2)$ transformations is a long-standing challenge. We solve the problem by expressing …