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HL: Fachverband Halbleiterphysik
HL 73: Semiconductor Surfaces (joint session O/HL)
HL 73.5: Hauptvortrag
Donnerstag, 19. März 2020, 16:00–16:30, REC C 213
Coupling of electronic and atomic degrees of freedom in surface-stabilized quasi-1D systems — •Wolf Gero Schmidt — Lehrstuhl für Theoretische Physik, Universität Paderborn
Minute structural changes may lead to drastic modifications of the electronic properties of quasi-1D systems, while, on the other hand, an electronic charge redistribution, induced, e.g., by optical excitations or surface vibrations may induce pronounced structural modifications in such systems. This is illustrated in my talk using two prominent examples: (i) Localized photoholes at the Brillouin zone boundary of the In/Si(111)(8x2) nanowire system are shown to drive an ultrafast (8x2) —→ (4x1) phase transitions that is accompanied by the formation of metallic In-In bonds along the wire direction [1,2]. (ii) A Si sp3 —→ sp2 + p rehybridization accompanied by a lateral surface charge transfer is demonstrated to destabilize the Si(553)-Au spin chains [3] with respect to a diamagnetic surface ground state that complies with electron counting heuristics [4]. Thermal excitation leads to soft Au chain vibrations that alter transiently the Au electron affinity and eventually the hybridization of the Si step edge atoms.
[1] T Frigge et al., Nature 544, 207 (2017).
[2] CW Nicholson et al., Science 362, 821 (2018).
[3] SC Erwin, FJ Himpsel, Nat. Commun. 1, 58 (2010).
[4] C Braun et al., PRB 98, 121402(R) (2018).