Optically excited structural transition in the In/Si(111) nanowire array at the quantum limit
ORAL
Abstract
The Si(111)-(4x1)/(8x2)In atomic wire array is an extremely popular model system for one-dimensional electronic systems. It features a reversible temperature-induced metal-insulator transition into a charge density wave (CDW) ordered ground state. The transition is driven by a strong electron-phonon coupling. We carried out constrained density functional theory calculations and ultrafast pump-probe electron diffraction measurements. We demonstrate that an optical excitation breaks and creates specific bonds, leading to a non-thermal excitation of particular soft phonon modes. The excitation of these modes drive the structural transition in the limit of critically damped nuclear motion and allows to switch between metallic and insulating states within 350 fs. This finding demonstrates that carefully tuned electronic excitations can create non-equilibrium potential energy surfaces that drive structural dynamics at interfaces in a regime of deterministic and directed nuclear motion [Nature 544, 207 (2017)].
*Financial support from the German Research Foundation (DFG), grant no. FOR1700 is gratefully acknowledged.
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Presenters
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Stefan Wippermann
- Interface Chemistry and Surface Engineering, Max Planck Inst fuer Eisenforschung GmbH
- Interface chemistry and surface engineering , Max Planck Inst fuer Eisenforschung GmbH
- GO, Max-Planck-Institute Duesseldorf
- Max Planck Inst für Eisenforschung GmbH