Exchange splitting of the three Γ ̄ surface states of Ni(111) from three-dimensional spin- and angle-resolved photoemission spectroscopy

The valence-band electronic structure of a clean Ni(111) surface is investigated by spin-resolved photoemission. At room temperature the orientation of the photoelectron spins on the Bloch sphere and the exchange splitting of surface and bulk states along the surface normal (Γ̅ ) are determined. All investigated states are found to have a sizable exchange splitting >50 meV. Since the splitting is smaller than the intrinsic line width in the spin-integrated spectrum this is only seen with a spin-resolved technique. At room-temperature photoemission reaching above the Fermi level directly shows that the Shockley type surface state S1 has an occupied majority and an unoccupied minority band with a splitting ΔEex=62±15 meV. The surface states below the Fermi energy show a larger exchange splitting for in-plane hybridization [ΔEex(S3)=160 meV] than for out-of-plane hybridization [ΔEex(S2)=55 meV]. Exchange splitting of the three Γ̄ surface states of Ni(111) from three-dimensional spinand angle-resolved photoemission spectroscopy T. Okuda,, J. Lobo-Checa, W. Auwärter , M. Morscher, M. Hoesch , V.N. Petrov , M. Hengsberger, A. Tamai, A. Dolocan, C. Cirelli, M. Corso, M. Muntwiler, M. Klöckner, M. Roos, J. Osterwalder, and T. Greber1∗ Physik Institut Universität Zürich, Winterthurerstrasse 190, CH 8057 Zürich, Switzerland The Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa 277-8581, Japan Swiss Light Source, Paul-Scherrer-Institut, CH 5232 Villigen PSI, Switzerland St. Petersburg Technical University, 29 Polytechnicheskaya Street, St. Petersburg 195251, Russia and University of Applied Sciences Winterthur, POB 805, CH 8401 Winterthur, Switzerland (Dated: October 6, 2009) Abstract The valence band electronic structure of a clean Ni(111) surface is investigated by spin-resolved photoemission. At room temperature the orientation of the photoelectron spins on the Bloch sphere and the exchange splitting of surface and bulk states along the surface normal (Γ̄) are determined. All investigated states are found to have a sizable exchange splitting >50 meV. Since the splitting is smaller than the intrinsic line width in the spin integrated spectrum this is only seen with a spin resolved technique. At room temperature photoemission reaching above the Fermi level directly shows that the Shockley type surface state S1 has an occupied majority and an unoccupied minority band with a splitting ∆Eex=62±15 meV. The surface states below the Fermi energy show a larger exchange splitting for in-plane hybridization (∆Eex(S3)=160 meV) than for out-of-plane hybridization (∆Eex(S2)=55 meV).The valence band electronic structure of a clean Ni(111) surface is investigated by spin-resolved photoemission. At room temperature the orientation of the photoelectron spins on the Bloch sphere and the exchange splitting of surface and bulk states along the surface normal (Γ̄) are determined. All investigated states are found to have a sizable exchange splitting >50 meV. Since the splitting is smaller than the intrinsic line width in the spin integrated spectrum this is only seen with a spin resolved technique. At room temperature photoemission reaching above the Fermi level directly shows that the Shockley type surface state S1 has an occupied majority and an unoccupied minority band with a splitting ∆Eex=62±15 meV. The surface states below the Fermi energy show a larger exchange splitting for in-plane hybridization (∆Eex(S3)=160 meV) than for out-of-plane hybridization (∆Eex(S2)=55 meV).