First-principles molecular dynamics at a constant electrode potential.
A simulation scheme for performing first-principles molecular dynamics at a constant electrode potential is presented, opening the way for a more realistic modeling of voltage-driven devices. The system is allowed to exchange electrons with a reservoir at fixed potential, and dynamical equations for the total electronic charge are derived by using the potential energy of the extended system. In combination with a thermostat, this potentiostat scheme reproduces thermal fluctuations of the charge with the correct statistics, implying a realistic treatment of the potential as a control variable. Practically, the dynamics of the charge are decoupled from the electronic structure calculations, making the scheme easily implementable in existing first-principles molecular dynamics codes. Our approach is demonstrated on a test system by considering various test cases.
National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Japan.
Nicéphore
N
Bonnet
Tetsuya
T
Morishita
Osamu
O
Sugino
Minoru
M
Otani
D004566:Electrodes; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D013816:Thermodynamics