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Fecher, Gerhard
Gerhard Fecher
Senior Chief Research Officer
Phone: +49 351 4646-2240
Fax: +49 351 4646-3002

Physics, Electronic structure

Publication highlight

1.
Julie Karel, Carlos E. ViolBarbosa, Janos Kiss, Jaewoo Jeong, Nagaphani Aetukuri, Mahesh G. Samant, Xeniya Kozina, Eiji Ikenaga, Gerhard H. Fecher, Claudia Felser, and Stuart S. P. Parkin, "Distinct Electronic Structure of the Electrolyte Gate-Induced Conducting Phase in Vanadium Dioxide Revealed by High-Energy Photoelectron Spectroscopy," ACS Nano 8 (6), 5784-5789 (2014).

HAXPES Investigation of Liquid Electrolyte Gating

New phase induced by electrolyte gating

The research in memristors and liquid electrolyte gating devices, where interfacial electric field induces modification throughout the film, requires spectroscopy investigation with large probe depth. HAXPES is the ideal technique to study these systems. We investigated the 3d orbital ordering of a VO2 thin film before and after been gated by ionic liquid electrolyte. The dependence of the photoemission intensity on the direction of the light electric field indicates a reduced orbital polarization in the gated state with respect to the monoclinic phase. A smaller orbital polarization is a direct consequence of the reduced vanadium dimerization, as shown schematically [1].

<div style="text-align: justify;"><strong>Figure 1:</strong> <em>Valence band of VO2 for pristine rutile and monoclinic state, and gated state.</em></div> Zoom Image
Figure 1: Valence band of VO2 for pristine rutile and monoclinic state, and gated state.
 
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