Orbital-dependent electron tunneling within the atom superposition approach: Theory and application to W(110)

K. Palotás, Gábor Mándi, L. Szunyogh

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

We introduce an orbital-dependent electron tunneling model and implement it within the atom superposition approach for simulating scanning tunneling microscopy (STM) and spectroscopy (STS). Applying our method, we analyze the convergence and the orbital contributions to the tunneling current and the corrugation of constant-current STM images above the W(110) surface. In accordance with a previous study, we find atomic contrast reversal depending on the bias voltage. Additionally, we analyze this effect depending on the tip-sample distance using different tip models and find two qualitatively different behaviors based on the tip orbital composition. As an explanation, we highlight the role of the real-space shape of the orbitals involved in the tunneling. STM images calculated by our model agree well with those obtained using Tersoff and Hamann's and Bardeen's approaches. The computational efficiency of our model is remarkable as the k-point samplings of the surface and tip Brillouin zones do not affect the computation time, in contrast to the Bardeen method.

Original languageEnglish
Article number235415
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number23
DOIs
Publication statusPublished - Dec 12 2012

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Electron tunneling
electron tunneling
Scanning tunneling microscopy
scanning tunneling microscopy
orbitals
Atoms
atoms
Bias voltage
Computational efficiency
Brillouin zones
sampling
Spectroscopy
Sampling
electric potential
Chemical analysis
spectroscopy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

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