Surface Studies by Low-Energy Electron Diffraction and Reflection High-Energy-Electron Diffraction

Laukkanen, P.; Sadowski, J.; Guina, Mircea

doi:10.1007/978-3-642-23351-7_1

Cited by 12 publications

(5 citation statements)

References 82 publications

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“…This is consistent with earlier reports in the literature that such domains can coexist [107]. The ×2 orders appear smeared for both reconstructions, which indicates the presence of disorder at the surface [108]. Whilst the LEED pattern reveals the size and orientation of the surface reconstruction, the precise atomic structure cannot easily be inferred from it, because LEED is only sensitive to the surface unit cell geometry and not the atomic positions inside the unit cell.…”

Section: Resultssupporting

confidence: 90%

Electronic structure of InAs and InSb surfaces: density functional theory and angle-resolved photoemission spectroscopy

Yang¹,

Schröter²,

Schuwalow³

et al. 2020

Preprint

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The electronic structure of surfaces plays a key role in the properties of quantum devices. However, surfaces are also the most challenging to simulate and engineer. Here, we study the electronic structure of InAs(001), InAs(111), and InSb(110) surfaces using a combination of density functional theory (DFT) and angle-resolved photoemission spectroscopy (ARPES). We were able to perform large-scale first principles simulations and capture effects of different surface reconstructions by using DFT calculations with a machine-learned Hubbard U correction [npj Comput. Mater. 6, 180 (2020)]. To facilitate direct comparison with ARPES results, we implemented a "bulk unfolding" scheme by projecting the calculated band structure of a supercell surface slab model onto the bulk primitive cell. For all three surfaces, we find a good agreement between DFT calculations and ARPES. For InAs(001), the simulations clarify the effect of the surface reconstruction. Different reconstructions are found to produce distinctive surface states. For InAs(111) and InSb(110), the simulations help elucidate the effect of oxidation. Owing to larger charge transfer from As to O than from Sb to O, oxidation of InAs(111) leads to significant band bending and produces an electron pocket, whereas oxidation of InSb(110) does not. Our combined theoretical and experimental results may inform the design of quantum devices based on InAs and InSb semiconductors, e.g., topological qubits utilizing the Majorana zero modes. I. INTRODUCTIONThe narrow-gap III-V semiconductors InAs and InSb (InX) have attractive material parameters, including small effective mass, large Lande g-factor, and large spin-

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Section: Resultssupporting

confidence: 90%

Electronic structure of InAs and InSb surfaces: density functional theory and angle-resolved photoemission spectroscopy

Yang¹,

Schröter²,

Schuwalow³

et al. 2020

Preprint

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show abstract

“…1b). Analysis of the elemental composition of the shells by EDS shows that the concentrations of Al and Mn in relation to gallium/with the reference to Ga are 18 and 5 at.%, respectively; which matches well the MBE calibrations performed for planar growth [10] with the same elemental flux intensities as used for the growth of NWs. Such a good agreement permits us to believe that our EDS measurements of the indium content in the shells reach the level of 8-9 at.%.…”

Section: Nw Cross-section By Fib Sectioning Methodssupporting

confidence: 76%

FIB Method of Sectioning of III-V Core-Multi-Shell Nanowires for Analysis of Core/Sell Interfaces by High Resolution TEM

et al. 2017

Self Cite

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The core-multishell wurtzite structure (In,Ga)As-(Ga,Al)As-(Ga,Mn)As semiconductor nanowires have been successfully grown on GaAs(111)B substrates using MBE technique. The nanowires cores were grown with gold eutectic catalyser in vapour-liquid-solid growth mode. The double shell overgrowth, on the side facets of nanowires, was performed using lower substrate temperature (about 400• C, and 230• C, for (Ga,Al)As, and (Ga,Mn)As shell growth, respectively). The polytypic ordering, defects, chemistry and geometric perfection of the core and the shells have been analysed at atomic level by advanced transmission electron microscope techniques with the use of axial and longitudinal section of individual nanowires prepared by focused ion beam. High quality cross-sections suitable for quantitative transmission electron microscope analysis have been obtained and enabled analysis of interfaces between the core and the shells with near atomic resolution. All investigated shells are epitaxial without misfit dislocations at the interface. Some of the shells thicknesses are not symmetric, which is due to the shadowing effects of neighbouring nanowires and directional character of the elemental fluxes in the MBE growth process.

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“…[ 111 ] The × 2 orders appear smeared for both reconstructions, which indicates the presence of disorder at the surface. [ 112 ] Whilst the LEED pattern reveals the size and orientation of the surface reconstruction, the precise atomic structure cannot easily be inferred from it, because LEED is only sensitive to the surface unit cell geometry and not the atomic positions inside the unit cell.…”

Section: Resultsmentioning

confidence: 99%

Electronic Structure of InAs and InSb Surfaces: Density Functional Theory and Angle‐Resolved Photoemission Spectroscopy

et al. 2022

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The electronic structure of surfaces plays a key role in the properties of quantum devices. However, surfaces are also the most challenging to simulate and engineer. Here, the electronic structure of InAs(001), InAs(111), and InSb(110) surfaces is studied using a combination of density functional theory (DFT) and angle‐resolved photoemission spectroscopy (ARPES). Large‐scale first principles simulations are enabled by using DFT calculations with a machine‐learned Hubbard U correction [npj Comput. Mater. 6, 180 (2020)]. To facilitate direct comparison with ARPES results, a “bulk unfolding” scheme is implemented by projecting the calculated band structure of a supercell surface slab model onto the bulk primitive cell. For all three surfaces, a good agreement is found between DFT calculations and ARPES. For InAs(001), the simulations clarify the effect of the surface reconstruction. Different reconstructions are found to produce distinctive surface states, which may be detected by ARPES with low photon energies. For InAs(111) and InSb(110), the simulations help elucidate the effect of oxidation. Owing to larger charge transfer from As to O than from Sb to O, oxidation of InAs(111) leads to significant band bending and produces an electron pocket, whereas oxidation of InSb(110) does not. The combined theoretical and experimental results may inform the design of quantum devices based on InAs and InSb semiconductors, for example, topological qubits utilizing the Majorana zero modes.

show abstract

Surface Studies by Low-Energy Electron Diffraction and Reflection High-Energy-Electron Diffraction

Cited by 12 publications

References 82 publications

Electronic structure of InAs and InSb surfaces: density functional theory and angle-resolved photoemission spectroscopy

Electronic structure of InAs and InSb surfaces: density functional theory and angle-resolved photoemission spectroscopy

FIB Method of Sectioning of III-V Core-Multi-Shell Nanowires for Analysis of Core/Sell Interfaces by High Resolution TEM

Electronic Structure of InAs and InSb Surfaces: Density Functional Theory and Angle‐Resolved Photoemission Spectroscopy

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