TITLE: Electronic surface states -- a theoretical and experimental perspective

SPEAKER: Yonas Abraham,

TIME: Thursday Nov. 18, 2004 at 2 PM^*

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

Photoelectron spectroscopy with pulsed laser excitation can provide a low-background, sensitive view of electronic states in the band gap¹ and photo-populated states above the Fermi level. Measurements of photoelectron emission for ultra-high vacuum cleaved surfaces of CdSe, excited by 4.5 and 5.9 eV Ti:sapphire laser pulses of 150 femtosecond duration are reported. One- and two-photon excitation processes are observed and analyzed in terms of features of the electronic structure.

In order to distinguish defect and surface contributions from the bulk properties of these systems, computer modeling methods are needed. Progress in designing numerical methods and algorithms for calculating the electronic structure of a material and its surface will be discussed.

¹ M. Yamada et al., Surf. Sci. 349 L107-L110 (1996).

100 Olin Physical Laboratory, 7507 Reynolda Station Wake Forest University Winston-Salem, NC 27109-7507 Phone: (336) 758-5337, FAX: (336) 758-6142 E-mail: wfuphys@wfu.edu	Quick Links Academics Research People Colloquia Info Physics