SURFACE VALENCE BANDS OF GASB(110) INVESTIGATED BY UV PHOTOEMISSION

Normal and off-normal photoemission experiments are performed with He I radiation on a GaSb(110) surface using a fast photoelectron analyzer . The results are compared with volume and surface electronic structur es calculated by the tight-binding method. Care is taken to distinguis h true surface emissions from diffracted secondary emissions, also cal led ''umklapp'' emissions. The umklapp bands can be followed in off-no rmal data with continuous variations which have not previously been ob served. Surface states at the top of the valence band and surface reso nances have been recognized. The tight-binding calculation of the ener gy dispersion of the umklapp bands confirms the allocation of these em issions (called S-1 and S-2). They seem very similar to those already reported for other group III-V compounds. (C) 1998 Elsevier Science B. V. All rights reserved.