Hidden surface states on pristine and H-passivated Ni(111): Angle-resolved photoemission and density-functional calculations

Abstract

By means of angle-resolved photoemission, we have uncovered surface related states on the pristine and hydrogen saturated Ni(111) surfaces. Near normal emission spectra were recorded at room temperature as a function of photon energy. A hidden Tamm surface state is found on the clean Ni(111) surface at a binding energy of ~1.19 eV, completely masked by the Lambda1 bulk d band. The existence of this surface state is in agreement with the density-functional theory calculations presented here. On the other hand, a surface state related to hydrogen adsorbed on the surface has been identified at a binding energy of ~0.22 eV. Under hydrogen exposure, it grows at the same rate as the three other surface states of the clean Ni (111)

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

“…In this letter we clarify the experimental situation with a spin analysis of the surface states along the surface normal of Ni(111). All surface states, including the third one that was also predicted by theory [8], but identified only recently [9], are found to be exchange split, though the splitting is lower than that of the bulk states. The magnitude of the splitting depends on the symmetry of the states and gives direct insight into the surface magnetism.…”

“…The main feature of the spectrum are the Λ 3 and Λ 1 bulk states. In addition to these strong bulk peaks, the three surface states labeled as S 1 , S 2 and S 3 can be seen as shoulders [9]. S 1 corresponds to the Shockley surface state that is also well known for other non-magnetic face centered cubic f cc (111) surfaces [12].…”

“…S 1 corresponds to the Shockley surface state that is also well known for other non-magnetic face centered cubic f cc (111) surfaces [12]. S 2 and S 3 are d band derived with out-of-plane and in-plane symmetry, respectively [9]. The Mott scattering asymmetry varies within the spectrum and indicates different spin polarizations for different photoelectron energies.…”

“…In Figure 3 the Gaussian peaks from the fitting to the data are shown, and the corresponding energy positions are listed in Table I. In Figure 3b) the region of the Λ 1 and the recently identified S 3 band [9] is shown. Although both, Λ 1 and S 3 are d band derived and are mainly in-plane hybridized, they do not have the same exchange splitting ∆E ex (Λ 1 ) > ∆E ex (S 3 ).…”

Formation of the BiAg2 surface alloy on lattice-mismatched interfaces

“…For example, Ag grows in a layer-by-layer mode on Ni(111), although the lattice mismatch is larger than that for both Cu(111) and Pt(111). Ni(111) supports spin-polarized electronic states and therefore the interplay between Rashba and exchange interactions could be investigated [28,29]. Although the BiAg 2 alloy has been previously grown on Si(111) [6][7][8], the Ag film thickness could be lowered and a Rashba surface state interface with a semiconductor substrate could be obtained.…”