Scattering theory of current-induced forces in mesoscopic systems
N. Bode, S. Viola Kusminskiy, R. Egger, F. von Oppen
Phys. Rev. Lett. 107, 036804 (2011), ( DOI:10.1103/PhysRevLett.107.036804 ) ;
Abstract: We develop a scattering theory of current-induced forces exerted by the conduction electrons of a general mesoscopic conductor on slow "mechanical" degrees of freedom. Our theory describes the current-induced forces both in and out of equilibrium in terms of the scattering matrix of the phase-coherent conductor. Under general nonequilibrium conditions, the resulting mechanical Langevin dynamics is subject to both non-conservative and velocity-dependent Lorentz-like forces, in addition to (possibly negative) friction. We illustrate our results with a two-mode model inspired by hydrogen molecules in a break junction which exhibits limit-cycle dynamics of the mechanical modes.