Electron spin-polarized photoemission

The following examples focus on valence level ionization by ultraviolet light, since such processes would produce low energy electrons, which are the most effective at inducing reactions in an adsorbed molecule. There are also many examples of spin-polarized photoemission and Auger electron emission from core levels of both magnetic and nonmagnetic materials [29-35]. 

Matthew JAD, Seddon EA, Xu YBO (1998) Spin polarized photoemission from amorphous alloy surfaces. J Electron Spectrosc Relat Phenomena 88-91 171-177... 

Meier, F. (1985) Polarized electrons in surface physics. In Spin Polarized Photoemission by Optical Spin Orientation in Semiconductors (ed. R. Feder). World Scientific, Singapore. Mendelsohn, L. B., Biggs, F. and Mann, J. B. (1970) Phys. Rev. A2, 1130. 

Thus spin polarized photoemission has been shown to be a new tool in giving information on the surface magnetization. Besides, efficient sources of spin polarized electrons can be made from e.g. EuO containing a few percent La and degrees of polarization of 80% at 30 kOe have been verified experimentally. 

Abstract Understanding the origin of chirality in nature has been an active area of research since the time of Pasteur. In this chapter we examine one possible route by which this asymmetry could have arisen, namely chiral-specific chemistry induced by spin-polarized electrons. The various sources of spin-polarized electrons (parity violation, photoemission, and secondary processes) are discussed. Experiments aimed at exploring these interactions are reviewed starting with those based on the Vester-Ulbricht hypothesis through recent studies of spin polarized secondary electrons from a magnetic substrate. We will conclude with a discussion of possible new avenues of research that could impact this area. 

Pierce DT, Meier F (1976) Photoemission of spin-polarized electrons from GaAs. Phys Rev B 13 5484... 

To deal with the electronic structure of surfaces within the framework of the spin-polarized relativistic KKR formalism, the standard layer techniques used for LEED and photoemission investigations (Pendiy 1974) have been generalized by several authors (Fluchtmann et al. 1995 Scheunemann et al. 1994). As an alternative to this, Szunyogh and co-workers introduced the so-called screened version of the KKR method (Szunyogh et al. 1994, 1995). A firm basis for this approach has been supplied by the tight-binding (TB) KKR scheme introduced by Zeller etal. (1995). The corresponding spin-polarized relativistic version has been applied by various authors to multilayer and surface-layer systems (Nonas et al. 2001). 

For magnetically ordered materials, photoemitted electrons have a characteristic spin polarization that reflects the electron spin orientation occurring in the sample before the photoemission process. Recently, techniques have been developed to measure this photoelectron spin polarization (photo ESP) (21). 

We report on the use of spin polarized electron beams in the study of electronic states in solids, referring in particular to the Inverse Photoemission spectroscopy. In this technique the empty electron states are investigated, and the spin resolution allows to study their spin character, yielding valuable information in magnetic systems. Examples of application to layered magnetic nanostructures are given in particular we present data on Fe/Cr/Fe(001) multilayers, ultrathin Fe films grown on ZnSe(OOl), and LaSrMnO/SnTiO junctions. 

Information on the spin resolved band structure of ferromagnetic materials can directly be obtained from spin resolving photoelectron spectroscopy. Using polarized radiation spin integrating photoemission techniques already enable to have access to magnetic properties. An enhancement of the surface sensitivity can be achieved using neutral excited spin polarized atoms which move towards the sample and are de-excited by tunneling electrons from the surface with a subsequent emission of electrons. 

The Cr02 electronic structure was solved only in 1987 by Kamper et al. [63]. Cr02 is a half-metallic ferromagnet that is, it is a metal for the majority (spin up) electrons, but exhibits a semiconductor-type gap for the majority (spin down) electrons (Figure 19.4). This picture was confirmed by a spin-resolved photoemission from polycrystalline Cr02 films, which showed a spin polarization of almost 100% for... 

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