Dresden 2017 – scientific programme

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O: Fachverband Oberflächenphysik

O 102: New Methods: Theory

O 102.2: Talk

Thursday, March 23, 2017, 18:00–18:15, WIL C107

Revised Chen’s derivative rule for STM calculations — Gábor Mándi¹ and •Krisztián Palotás^1,2 — ¹Budapest University of Technology and Economics, Budapest, Hungary — ²Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia

Chen’s derivative rule for electron tunneling [1] is revised [2] for the purpose of computationally efficient calculations of scanning tunneling microscopy (STM). New features include (i) the weighting of tunneling matrix elements of different tip-orbital characters by an arbitrary energy-independent choice or based on first-principles data, (ii) arbitrary tip geometrical orientations, and (iii) the possibility of quantitative analysis of tip-orbital interference contributions. The model is applied to two functionalized surfaces where quantum interference effects play an important role in the STM imaging and the Tersoff-Hamann model fails to describe the correct STM contrast under certain conditions: N-doped graphene [3] and a magnetic Mn₂H complex on the Ag(111) surface [4]. For both studied surfaces, the importance of interference between s and p_z tip orbitals is highlighted that cause a significant contrast change in the STM images [2].

[1] C. J. Chen, Phys. Rev. B 42, 8841 (1990)

[2] G. Mándi, K. Palotás, Phys. Rev. B 91, 165406 (2015)

[3] M. Telychko et al., ACS Nano 8, 7318 (2014)

[4] T. Sachse et al., New J. Phys. 16, 063021 (2014)