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

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 [Heinze et al., Phys. Rev. B 58, 16432 (1998)], 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 Tersoff-Hamann and Bardeen results. 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.

28 pages manuscript, 7 figures, 1 table

References in corpus (2)

• Simulation of inelastic electron tunneling spectroscopy of single molecules with functionalized tips
• Theoretical study of the role of the tip in enhancing the sensitivity of differential conductance tunneling spectroscopy on magnetic surfaces

Cited by in corpus (4)

• Chen's derivative rule revisited: Role of tip-orbital interference in STM
• What is the orientation of the tip in a scanning tunneling microscope?
• Prediction of the bias voltage dependent magnetic contrast in spin-polarized scanning tunneling microscopy
• Contrast stability and "stripe" formation in Scanning Tunnelling Microscopy imaging of highly oriented pyrolytic graphite: The role of STM-tip orientations