Bismuth-stabilized (2x1) and (2x4) reconstructions on GaAs(100) surfaces : Combined first-principles, photoemission, and scanning tunneling microscopy study

• Bismuth adsorbate-stabilized (2x1) and (2x4) reconstructions of the GaAs(100) surfaces have been studied by first-principles calculations, valence-band and core-level photoelectron spectroscopies, and scanning tunneling microscopy. It is demonstrated that large Bi atom size leads to the formation of the pseudogap at the Fermi energy and to the lower energy of an adsorbate-derived surface band, which contributes to the stabilization of the exceptional Bi/GaAs(100)(2x1) reconstruction. It is proposed that the Bi/GaAs(100)(2x4) reconstructions include asymmetric mixed Bi-As dimers, in addition to the Bi-Bi dimers. Based on the calculations, we solve the atomic origins of the surface core-level shifts (SCLSs) of the Bi 5d photoemission spectra from the Bi/GaAs(100)(2x4) surfaces. This allows for resolving the puzzle related to the identification of two SCLS components often found in the measurements of the Bi 5d and Sb 4d core-level emissions of the Bi/III-V and Sb/III-V(100)(2x4) surfaces. Finally, the reason for the absence of the common (2x4)-beta 2 structure and additional support for the stability of the (2x1) structure on the Bi/III-V(100) surfaces are discussed in terms of Bi atom size and subsurface stress.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

ab initio calculations

adsorbed layers

bismuth

core levels

energy

gap

Fermi level

gallium arsenide

III-V semiconductors

photoelectron

spectra

scanning tunnelling microscopy

surface reconstruction

valence bands

semiconductor 001 surfaces

initio molecular-dynamics

total-energy

calculations

augmented-wave method

x 4) surface

atomic-structure

electronic-structure

basis-set

bi

gaas(001)

surface reconstruction

scanning tunnelling microscopy

spectra

photoelectron

III-V semiconductors

gallium arsenide

Fermi level

gap

energy

core levels

bismuth

ab initio calculations

adsorbed layers

valence bands

Physics

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)