dxz/yz orbital subband structures and chiral orbital angular momentum in the (001) surface states of SrTiO3

We performed angle-resolved photoemission spectroscopy (ARPES) experiments on the surface states of SrTiO3(001) using linearly and circularly polarized light to investigate the subband structures of out-of-plane d(xz/yz) orbitals and chiral orbital angular momentum (OAM). The data taken in the first Brillouin zone reveal new subbands for d(xz/yz) orbitals with Fermi wave vectors of 0.25 and 0.45 angstrom(-1) in addition to the previously reported ones. As a result, there are at least two subbands for all the Ti 3d t(2g) orbitals. Our circular dichroism ARPES data are suggestive of a chiral OAM structure in the surface states and may provide clues to the origin of the linear Rashba-like surface band splitting.