Density matrix approach to photon-assisted tunneling in the transfer Hamiltonian formalism

Abstract

The transfer Hamiltonian tunneling current is derived in a time-dependent density matrix formulation and is used to examine photon-assisted tunneling. Bardeen's tunneling expression arises as the result of first order perturbation theory in a mean-field expansion of the density matrix. Photon-assisted tunneling from confined electromagnetic fields in the forbidden barrier region occurs due to time-varying polarization and wavefunction overlap in the gap, which leads to a non-zero tunneling current in asymmetric device structures, even in an unbiased state. The photon energy is seen to act as an effective temperature dependent bias in a uniform barrier asymmetric tunneling example problem. Higher order terms in the density matrix expansion give rise to multi-photon enhanced tunneling currents that can be considered an extension of non-linear optics where the non-linear conductance plays a similar role as the non-linear susceptibilities in the continuity equations.

8 pages, 2 figures

References in corpus (2)

• Thermoelectric energy harvesting with quantum dots
• Powerful and efficient energy harvester with resonant-tunneling quantum dots

Cited by in corpus (4)

• Fluctuation dissipation relations for strongly correlated out-of-equilibrium circuits
• Power generation from a radiative thermal source using a large-area infrared rectenna
• Consistent analytical solution for the response of a nanoscale circuit to a mode-locked laser
• Possibility of coherent electron transport in a nanoscale circuit