The minority spin surface bands of CoS₂(001)

Abstract

Lozova, N.; Manno, M.; Leighton, C.; and Dowben, Peter A., "The minority spin surface bands of CoS 2 (001)" (2009 Abstract Angle-resolved photoemission was used to study the surface electronic band structure of high quality single crystals of ferromagnetic CoS 2 (below 120 K). Strongly dispersing Co t 2g bands are identified along the 100 k direction, the¯ -X line of the surface Brillouin zone, in agreement with model calculations. The calculated surface band structure includes corrections for the previously determined surface structure of CoS 2 (001) and is in general agreement with the experimental photoemission spectra in the region of the Fermi level. There is evidence of the existence of several minority spin surface states, falling into a gap of the projected minority spin bulk CoS 2 (001) band structure.

Ce-doped EuO: Magnetic properties and the indirect band gap

“…The combined photoemission and inverse photoemission studies were carried out as described elsewhere, 12 while angle-resolved high resolution photoemission studies were used to map the wave-vector-dependent density of states in the vicinity of the Fermi level, following a recipe also described elsewhere. 13 As shown in Fig. 1 Author to whom correspondence should be addressed.…”

Resonant photoemission and spin polarization of Co1−xFexS2

“…While the complications of preferential sputtering or segregation are considered in the discussion that follows, there is no evidence to indicate either occurs in a significant manner in these experiments: resonant photoemission ratio of intensities, discussed below, are consistent with the nominal composition. The alternatives of cleaving the sample (as in [21,[23][24][25]) or scraping the surface (as in [26]), to prepare a clean surface, were not an option here.…”

“…In either case, the surface would essentially not be the same material as the bulk. What must be considered however is that this small spin polarization might occur due to minority spin states close to the Fermi level, which have been identified to exist for the pure CoS 2 (100) surface [21]. These minority spin states would provide a surface signal that would diminish the net spin polarization observed from the majority spin states, causing a decrease in the measured surface spin polarization.…”

“…Consistent with this hypothesis is the fact that we find strong evidence for Fe-S and Co-S hybridization that scales as expected with the respective iron and cobalt concentrations. Figure 2 shows broad features in the photoemission spectra with binding energies between −3 and −8 eV with strong S 3p band weight [6,21,24] and strong dispersion with photon energy [24]. To demonstrate that these valence band features do contain some Co and Fe contributions, and hence show the essential transition metal hybridization with the S bands, resonant photoemission experiments were undertaken.…”

Calculation on surface energy and electronic properties of CoS 2

“…[ 14 ] predicted that the half-metallic gap might be controlled by antibonding S p rather than Co e g states by calculating the electronic band structure of CoS 2 . They also discussed the spin bands of CoS 2 (001) by experiment and computation [ 15 ]. Liu & Altounian [ 16 ] studied the effect of pressure on the itinerant ferromagnet CoS 2 by first principles.…”