A study of the Heusler alloy using ultraviolet photoemission spectroscopy

Abstract

Ultraviolet photoemission spectroscopy has been employed to provide information on the valence band of the Heusler alloy. The contribution of the d bands of Mn and Cu to the density of states has been investigated by means of 3p to 3d resonant enhancement. The valence band extends to 6 eV below the Fermi level, with a main peak at a binding energy of 3.2 eV and a shoulder extending to the Fermi edge. Resonant photoemission indicates that the Mn 3d character extends across the full width of the band. An experimental photoemission spectrum obtained at a photon energy of 40 eV has been compared with a calculated spectrum derived from a theoretical band structure. The main difference occurs in the region 1 - 2 eV below the Fermi level. The calculated spectrum exhibits a peak at a binding energy of 1.5 eV, comprising contributions from both the Cu and Mn 3d bands. There is no evidence of a similar feature in the experimental spectrum.

Photoelectron spectroscopy of manganese-based Heusler alloys

“…Comparing these results with earlier photoemission measurements on Heusler alloys, it is apparent that the shape of the valence band of Co 2 MnSn is very similar to that of Ni 2 MnSb, 28 while the valence band of Pd 2 MnSn resembles that of Pd 2 TiSn. 29 The spectrum obtained for Cu 2 MnAl has been reported in an earlier paper 30 and is very similar to that obtained in a separate photoemission study using a He I (21.2 eV) source. 31 Investigating each alloy in more detail, the Co containing sample will be considered first.…”

“…To model lifetime effects, the bands were convoluted with Lorentzians of HWHM varying in proportion with the square of the binding energy from zero at E F to 0.6 eV at the bottom of the band. 30 The data were then further convoluted with a Gaussian function of width corresponding to the estimated experimental resolution. The convoluted PDOS were then normalized so that the area under each curve corresponded to the fractional contribution of d electrons supplied by Co and Mn to the valence band.…”

Ab initioand photoemission study of correlation effects in SrRuO3thin films

“…After background subtraction the VB photoemission spectrum for SrRuO 3 can be calculated for a particular photon energy using the following approximate expression (DOS approximation): [40][41][42] …”

Electronic structure of the Cu2MnAl Heusler alloy

“…They also pointed out that there was no 3d spin moment at the Cu site, while that of the Mn site is 3.25 µ B , which is consistent with the neutron experiment but disagrees with the theoretical calculation. The ultraviolet photoemission spectrum of Cu 2 MnAl Heusler alloy has been obtained by Brown et al [22]. The measured spectrum reveals that the Mn 3d character extends across the full width of the valence bands.…”