Chiral Orbital Angular Momentum and Circular Dichroism ARPES in p- and d-orbital Bands

We derive explicit formulas relating the circular dichroism angle-resolved photoemission (CD-ARPES) signal to the existence of nonzero chiral orbital angular momentum (OAM) in the band structure. The existence of nonzero chiral OAM is a generic feature of surface states that break inversion symmetry, as pointed out in several recent articles [1-3]. We propose that CD-ARPES setup is an effective probe of the OAM of quasi-particles occupying the surface states. Explicit formulas for the $p$- and $d$-orbital bands are derived to show that the CD-ARPES signal is proportional to the OAM in the momentum space.\\[4pt] [1] S. R. Park, C. H. Kim, J. Yu, J. H. Han and C. Kim, Phys. Rev. Lett. \textbf{107}, 156803 (2011).\\[0pt] [2] S. R. Park \textit{et al}., arXiv:1103.0805 (2011).\\[0pt] [3] Choong H. Kim \textit{et al}., arXiv:1107.3285 (2011).