Abstract
We discuss the Pauli Hamiltonian including the spin-orbit interaction within an U(1)×SU(2) gauge theoryinterpretation, where the gauge symmetry appears to be broken. This interpretation offers new insight intothe problem of spin currents in the condensed matter environment, and can be extended to Rashba andDresselhaus spin-orbit interactions. We present a few outcomes of the present formulation: i) it automaticallyleads to zero spin conductivity, in contrast to predictions of Gauge symmetric treatments, ii) a topologicalquantization condition leading to voltage quantization follows, and iii) spin interferometers can be conceivedin which, starting from a arbitrary incoming unpolarized spinor, it is always possible to construct a perfectspin filtering condition.Key words: Spin-orbit interaction, Gauge field theory, Spin transport, Spin Hall effectPACS: 75.25.+z Spin arrangements in magnetically ordered materials (including neutron and spin-polarizedelectron studies, synchrotron-source X-ray scattering, etc.)85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magneticfields03.65.Vf Phases: geometric; dynamic or topological
Highlights
A reformulation of the spin-orbit (SO) coupling Hamiltonian in terms of non-Abelian gauge fields [1] was explicitly given in [2,3,4,5] where the SO interaction is presented as a SU (2) × U (1) gauge theory
A consistent SU (2) × U (1) gauge approach was presented in reference [4,5] where it was found that for the Pauli type Hamiltonians, Gauge Symmetry Breaking (GSB) is necessarily built into the theory and leads to the spin conductivity vanishing in constant electric fields [5]
If cos Λ = 0, the operator Ua is diagonal in the input spinor basis, which means that a perfect spin filtering is possible in this original basis if one of the two eigenvalues λa± vanishes
Summary
A reformulation of the spin-orbit (SO) coupling Hamiltonian in terms of non-Abelian gauge fields [1] was explicitly given in [2,3,4,5] where the SO interaction is presented as a SU (2) × U (1) gauge theory. As the Yang-Mills gauge theory is well understood and is the underpinning of well established theory, enormous insight can be brought upon new problems. Such gauge point of view, in more general terms, has been known for some time [6,7,8,9]. The Rashba and Dresselhaus SO interactions arise in materials which lack either structural or bulk inversion symmetry, respectively [11,12,13] These two kinds of interactions have recently been given a great deal of attention due to their potential role in the generation and manipulation of spin polarized currents, spin filters [14], spin accumulation [15], and spin optics [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
