On STM imaging of GaAs(0 0 1)-( n×6) surface reconstructions: Does the (6×6) structure exist?

• Published in: Surface science 2002-07, Vol.513 (2), p.249-255
• Main Authors: Xu, Hai, Li, Y.G., Wee, A.T.S., Huan, C.H.A., Tok, E.S.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Gallium arsenide; Low energy electron diffraction (LEED); Phase transitions and critical phenomena; Physics; Scanning tunneling microscopy; Solid surfaces and solid-solid interfaces; Surface relaxation and reconstruction; Surface thermodynamics (including phase transitions); Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); X-ray photoelectron spectroscopy
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(02)01820-4

The ultrahigh vacuum scanning tunneling microscope (UHV-STM) was employed to investigate the evolution of GaAs(0 0 1)-( n×6) surface reconstructions. The ( n×6) surface reconstructions have been referred to as As-rich transitional phases comprising of (1×6), (2×6), (3×6) and (6×6) reconstructions. During the evolution from ( n×6) to the Ga-rich (4×2) reconstruction, our dual-bias ( n×6) STM images reveal one alternating single As dimer chain with a periodicity giving n=2; and a pair of Ga dimer rows between the As chains with a periodicity of n=3, which has not been previously reported. A new (6×6) reconstruction model is proposed based on the atomic resolution dual bias STM images obtained; and we discuss whether such (6×6) reconstructions exist in the light of all STM data published to date.