Bias-dependence of the appearance of scanning tunnelling microscope images of the GaAs(001)-(2 × 4) surface reconstruction

Autor: D. A. Woolf, Peter Weightman, J. M. C. Thornton, M. D. Jackson
Rok vydání: 1996
Předmět:
Zdroj: Surface Science. :724-729
ISSN: 0039-6028
Popis: The (2 × 4) reconstruction of the (001) surface of GaAs has been studied using scanning tunnelling microscopy (STM) and spectroscopy. The images, produced at several biases, show coexisting two dimer and three dimer surface unit cell reconstructions. By examining line profiles across the dimers, we find an asymmetry in the two dimer surface unit cell reconstruction which changes with the sample bias. The images of the three dimer surface unit cell reconstruction are also shown to be different at different biases. A spectroscopic spectrum is presented which gives insight into the origin and characteristics of negative and positive bias tunnelling. Our results are compared to theoretical studies of the expected appearance of STM images under different bias conditions and the implications of the findings are discussed.
Databáze: OpenAIRE