Evidence from scanning tunneling microscopy in support of a structural model for the InSb(001)-c(8×2) surface

Abstract

In this letter we present evidence from scanning tunneling microscopy studies in support of a recently proposed structural model for the indium-terminated c(8ϫ2) surface of InSb͑001͒. This structural model, by Norris and co-workers, is based on a surface x-ray diffraction study ͓Surf. Sci. 409, 27 ͑1998͔͒, and represents a significant departure from previously suggested models for the c(8ϫ2) reconstruction on any ͑001͒ surface of the common III-V semiconductor materials. Although filled state images of the InSb(001)-c(8ϫ2) surface have previously been published, empty states image of sufficient quality to extract any meaningful information have not previously been reported. The observations are in excellent agreement with the recently proposed model for this surface reconstruction.

Electronic structure of InSb (001), (110), and (111)B surfaces

“…1(b) with the unit cell outlined in blue. The STM images of the c(8x2) surface are consistent with prior studies of the c(8x2) surface [19][20][21][22][23][24] . Additionally, round defects are present in the STM image.…”

“…The surface reconstruction unit cell is outlined in blue. A ball and stick model 21 of the c(8x2) surface reconstruction is shown in Fig. 1(b) with the unit cell outlined in blue.…”

“…While many of the clean InSb surfaces have been imaged with STM [18][19][20][21][22][23][24][25][26][27][28][29][30] , there have been only a few studies on the surface electronic structure of InSb with STS 25,30,31 . Most STS studies of InSb have been on the cleaved (110) (1x1) surface 25,31 , which have demonstrated the cleaved surface can be unpinned and devoid of surface states within the semiconductor band gap.…”

Structure of metal-rich (001) surfaces of III-V compound semiconductors

“…1,8,13 In more recent STM work on InSb additional weak features indicating the c(8ϫ2) unit cell were found. 8,15 Skala and co-workers modified the group-III-dimer model suggesting additionally group-V dimers on top of double rows of group-III atoms, 16 a model again based on STM measurements on GaAs ͓see Fig. 1͑d͔͒.…”

“…Their model contains no group-III dimers and was supported by a reinterpretation of STM images. 15 Recently a completely different model was proposed independently by two groups; theoretical total-energy calculations combined with a LEED analysis 18 by one group and direct methods applied to SXRD data by the other. 19 The present article is an extension of the latter work.…”