Mapping the wavefunction of transition metal acceptor states in the GaAs surface

Abstract

We utilize a single atom substitution technique with spectroscopic imaging in a scanning tunneling microscope (STM) to visualize the anisotropic spatial structure of magnetic and non-magnetic transition metal acceptor states in the GaAs (110) surface. The character of the defect states play a critical role in the properties of the semiconductor, the localization of the states influencing such things as the onset of the metal-insulator transition, and in dilute magnetic semiconductors the mechanism and strength of magnetic interactions that lead to the emergence of ferromagnetism. We study these states in the GaAs surface finding remarkable similarities between the shape of the acceptor state wavefunction for Mn, Fe, Co and Zn dopants, which is determined by the GaAs host and is generally reproduced by tight binding calculations of Mn in bulk GaAs [Tang, J.M. & Flatte, M.E., Phys. Rev. Lett. 92, 047201 (2004)]. The similarities originate from the antibonding nature of the acceptor states that arise from the hybridization of the impurity d-levels with the host. A second deeper in-gap state is also observed for Fe and Co that can be explained by the symmetry breaking of the surface.

19 pages, 6 figures

References in corpus (12)

• Atom-by-Atom Substitution of Mn in GaAs and Visualization of their Hole-Mediated Interactions
• Spatial structure of an individual Mn acceptor in GaAs
• Unusual direction dependence of exchange energies in GaAs:Mn - Is the RKKY description relevant
• First-principles investigation of the assumptions underlying Model-Hamiltonian approaches to ferromagnetism of 3d impurities in III-V semiconductors
• Multiband tight-binding model of local magnetism in GaMnAs
• Influence of non-local exchange on RKKY interactions in III-V diluted magnetic semiconductors
• Electronic and structural properties of vacancies on and below the GaP(110) surface
• Symmetric Versus Nonsymmetric Structure of the Phosphorus Vacancy on InP(110)
• STM images of sub-surface Mn atoms in GaAs: evidence of hybridization of surface and impurity states
• On the Connection of Anisotropic Conductivity to Tip Induced Space Charge Layers in Scanning Tunneling Spectroscopy of p-doped GaAs
• Influence of surface-related strain and electric field on acceptor wave functions in Zincblende semiconductors
• Kinetic stabilization of Fe film on (4 by 2)-GaAs(100)

Cited by in corpus (9)

• Colloquium: Atomic spin chains on surfaces
• Magnetic interactions of substitutional Mn pairs in GaAs
• High-temperature intrinsic ferromagnetism in heavily Fe-doped GaAs layers
• Spatially resolved electronic structure of an isovalent nitrogen center in GaAs
• Electronic structure and magnetic properties of Mn and Fe impurities near GaAs (110) surface
• Observation of the symmetry of core states of a single Fe impurity in GaAs
• Fine structure of neutral acceptor states of isolated impurity in zinc-blende semiconductors
• Electric manipulation of the Mn-acceptor binding energy and the Mn-Mn exchange interaction on the GaAs (110) surface by nearby As vacancies
• Atomic scale visualization of the p-d hybridization in III-V semiconductors doped with transition metal impurities