SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 67: Poster: Electronic Structure of Surfaces

O 67.1: Poster

Mittwoch, 29. März 2023, 18:00–20:00, P2/EG

Fermi-level pinning at InP(001):H surfaces — •Rachele Sciotto, Isaac Azahel Ruiz Alvarado, and Wolf Gero Schmidt — Lehrstuhl für Theoretische Materialphysik, Universität Paderborn, 33095 Paderborn, Germany

Stable InP(001):H surfaces are characterized by fully occupied and empty surface states close to the bulk valence and conduction band edges, respectively [1]. However, photoemission shows a surface Fermi level pinning at midgap energy [2]. In order to resolve that apparent discrepancy, we perform density-functional calculations. Ab initio thermodynamics is used to determine the density of surface defects as a function of temperature and hydrogen pressure. The influence of spin polarization and charging on the electronic properties of the surface defects is studied in detail. It is found that in particular P dangling bonds resulting from H desorption give rise partially filled midgap electronic states that are suitable to explain the experimental findings.

[1] WG Schmidt, et al. Phys. Rev. Lett. 90, 126101 (2003); PH Hahn, WG Schmidt, Surf. Rev. Lett. 10, 163 (2003).

[2] DC Moritz, et al. ACS Appl. Mater. Interfaces 14, 47255 (2022).