Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 74: Graphene: Electronic Properties, Structure and Substrate Interaction II (joint session DY, DS, HL, MA, O, TT, organized by O)
TT 74.3: Talk
Thursday, March 23, 2017, 15:30–15:45, TRE Ma
Controlling intramolecular hydrogen-transfer by electrostatic doping using gate-tunable STM — •Shai Mangel1, Christian Dette1, Katharina Polyudov1, Paul Punke1, Roberto Urcuyo1, Marko Burghard1, Soon Jung Jung1, and Klaus Kern1,2 — 1Max-Planck-Institute for Solid State Research, D-70569 Stuttgart — 2École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
Electron transport properties can be controlled by intramolecular reactions that reshape the electronic configuration without changing the conformation. A prominent example is tautomerization, i.e. the interconversion between two isomers due to migration of hydrogen, which can be induced by STM. Several methods to control the tautomerization reaction were developed, such as depositing adatoms or using thermal and photoinduced excitation. However, those methods are usually limited in their spatial range and not always reversible. In this work, we demonstrate a global control of the electron density surrounding H2-phthalocyanine on graphene/SiO2/Si. By using a gate-tunable STM, we electrostatically doped the graphene substrate altering the chemical potential in the molecules surrounding, which results in up to 60% decrease of the tautomeric switching rate. This reduction is assigned to an increase in the energetic barrier of the tautomerization reaction. Understanding and controlling the electric field-effect on molecules via modification of the chemical potential of graphene is critical for designing future molecular electronic devices.