Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 30: 1D Metal Wires on Semiconductors I
O 30.7: Talk
Tuesday, March 8, 2016, 12:15–12:30, S052
Phase transition of In-Si(111) (4x1)- (8x2) nanowires in a new light — •Eugen Speiser1, Stefan Wippermann2, Simone Sanna3, Wolf Gero Schmidt3, Sandhya Chandola1, and Norbert Esser1 — 1ISAS e.V., Schwarzschildstraße 8, 12489 Berlin, Germany — 2Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237 Düsseldorf, Germany — 3Lehrstuhl für Theoretische Physik, Universität Paderborn, 33095 Paderborn, Germany
Although recognized as a model case for atomic metallic nanowires, the (4x1)-(8x2) phase transition continues to hide behind the complexity of the structure and electronical properties. In cooperation with continuously developing theoretical methods a variety of conventional and newly developed experimental surface investigation methods are actively applied to elucidate the underlying mechanism of the phase transition. Our approach to this problem is the joint work of calculations and measurements of the low energy surface vibrations localized in the top layer. Successful assignment of calculated vibrational patterns and frequencies to measurements of both the insulating (8x2) and metallic (4x1) phases, is a necessary requirement to understand the dynamics of each phase. Based on this knowledge an interpretation of temperature dependency of phonon frequencies near the phase transition will be given in terms of participation of the electron phonon coupling to the phase transition mechanism. Coupling parameters between phonons and electrons can be estimated from an empirical model based on Landau-Ginsberg theory, as already verified in 1D like bulk materials, eg. blue bronze.