Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 9: Nanostructures at Surfaces I

O 9.7: Talk

Monday, March 7, 2016, 12:00–12:15, H6

Controlled creation and imaging of quantum states of dangling bond structures on H-terminated Si(001) — •Asif M Suleman, Kian A Rahnejat, Cyrus F Hirjibehedin, Neil J Curson, Gabriel Aeppli, David R Bowler, and Steven R Schofield — University College London, London, UK

An understanding of how semiconductor point defects interact is needed if they are to fulfil their potential as the basis of future nanoelectronic and quantum devices. Scanning tunnelling microscopy (STM) has been used to investigate point defects on semiconductor surfaces. Here we present an investigation of interacting dangling bond (DB) orbitals on H-terminated Si(001). The STM tip is used to selectively desorb individual H atoms to create a DB [1]. Pairs, or dimers, of DBs interact as their individual excited states overlap, signalled by the appearance of a bright protrusion between them in a molecular-like state [2]. Tip-induced band bending calculations show this excited molecular state of the dimer come into tunnelling range at high biases and low currents. The energy alignment with the tip Fermi level is also affected by additional DBs in the vicinity of the dimer. 2D structures of DBs, including trimers and tetramers, were produced that exhibit 2D extended excited molecular states that we present here for the first time. By modelling each DB with a 2D Pöschl-Teller potential well holding two bound states, we could simulate the bound states for the DB structure and find good agreement with experiment. [1] J. W. Lyding et al. Appl. Phys. Lett. 64, 2010 (1994). [2] S. R. Schofield et al. Nat. Commun. 4, 1649 (2013). [3] A. M. Suleman et al. In prep. (2015).