Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 82: Metal Substrates II
O 82.4: Talk
Thursday, April 3, 2014, 16:45–17:00, WIL A317
Electromechanical coupling coefficients of sp-bonded metals from first principles — •Anja Michl1,2, Sandra Hoppe2, Chandramouli Nyshadham2, Jörg Weissmüller1,3, and Stefan Müller2 — 1Institute of Materials Research, Materials Mechanics, Helmholtz-Zentrum Geesthacht, Germany — 2Institute of Advanced Ceramics, Hamburg University of Technology, Germany — 3Institute of Materials Physics and Technology, Hamburg University of Technology, Germany
The coupling between mechanical stress or strain of a surface and its electronic properties is relevant for various applications ranging from sensors and actuators to catalysis. In experiment, coupling coefficients are determined via electrochemical experiments, e.g. by measuring the variation of the electrode potential upon applying tangential strain e to the electrode surface. Theoretically, this coupling strength is accessible as the response of the electronic work function W to strain. Using density functional theory, we calculate such strain response parameters dW/de for sp-bonded metals. While for Al we find an abnormal positive sign for the coupling coefficient [1], all other investigated metals show the usual negative response parameter (in their natural crystal structure). We analyze trends of the coupling coefficients with respect to valence electron density, crystal structure and work function of the unstrained surface and discuss the identified correlations.
[1] A. Michl, J. Weissmüller and S. Müller, J. Phys.: Condens. Matter 25, 445012 (2013)