2011/12/12 by Beomyoung Kim, Choong H. Kim, Panjin Kim +12 · 2 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Angular momentum #Angular momentum coupling #Atomic orbital #Atomic physics #Condensed matter physics #Electron #Geometry #Hamiltonian (control theory) #Physics #Point reflection #Quantum and electron transport phenomena #Quantum mechanics #Spin (aerodynamics) #Spins #Spin–orbit interaction #Surface (topology) #Surface states #Topological Materials and Phenomena #Total angular momentum quantum number #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.85.195402
arxiv created 2011/12/12 · openalex publication_date 2012/05/02 · arxiv updated 2013/05/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We performed angle-resolved photoemission studies on Cu(111) and Au(111) surface states with circularly polarized light to investigate local orbital angular momentum (OAM) structures. Existence of OAM is confirmed, as predicted, to exist in systems with an inversion symmetry breaking. Cu(111) surface state bands are found to have chiral OAM in spite of very small spin-orbit coupling, consistent with the theoretical prediction. As for Au(111), we observe split bands for which OAM for the inner and outer bands are parallel, unlike the Bi2Se3 case. We also performed first-principles calculations and the results are found to be consistent with experimental results. Moreover, the majority of OAM is found to have d-orbital origin while a small contribution comes from p orbitals. An effective Hamiltonian that incorporates the role of OAM is derived and is used to extract the spin and OAM structures. We discuss the evolution of angular momentum structures from a pure OAM system to a strongly spin-orbit-entangled state. We predict that the transition occurs through a reversal of the OAM direction at a k point in the inner band if the system has a proper spin-orbit coupling strength.