Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 29: Metallic nanowires on semiconductor surfaces

O 29.3: Vortrag

Dienstag, 13. März 2018, 11:00–11:15, MA 144

Light-induced phase transition in one-dimensional Indium wires — •Mariana Chavez-Cervantes, Razvan Krause, Sven Aeschlimann, and Isabella Gierz — Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany

Strong Fermi surface nesting in one-dimensional wires drives Peierls transitions where a periodic lattice distortion opens up a band gap at the Fermi level. The In/Si(111)-(4x1) surface consists of quasi-one-dimensional indium wires which are metallic at high temperatures and become insulating below Tc~100K via a complex three-band Peierls transition assisted by interband charge transfer [1]. We study the light-induced insulator-to-metal phase transition using time- and angle-resolved photoemission spectroscopy (tr-ARPES), complementing recent investigations of the underlying lattice dynamics [2-3]. We observe closing of the band gap on a timescale (~500fs) that is a fraction of the amplitude mode period. The recovery time of the insulating state is found to be strongly fluence dependent with trapping in a meta-stable (4x1) phase at high fluences. We discuss the subtle role of the chemical potential [4] for both the temperature- and the light-induced phase transition.

[1]P. C. Snijders et al., Rev. Mod. Phys. 82, 307(2010)

[2]S. Wall et al., PRL 109,186101 (2012)

[3]T. Frigge et al., Nature 544, 207 (2017)

[4]E. Jeckelmann et al., Phys. Rev. B 93, 241407(R) (2016)