Charge pumping and photovoltaic effect in open quantum dots

Abstract

We propose a random matrix theory to describe the influence of a time-dependent external field on electron transport through open quantum dots. We describe the generation of the current by an oscillating field for the dot, connected to two leads with equal chemical potentials. For low frequency fields our results correspond to adiabatic charge pumping. Finite current can be produced if the system goes along a closed loop in parameter space, which covers a finite area. At high frequency a finite current is produced even if the loop is a line in parameter space. This result can be explained in the same way as adiabatic pumping but considering the evolution of the system in phase space rather than in parametric space.

Photovoltaic Current Response of Mesoscopic Conductors to Quantized Cavity Modes

“…In the classical description of EM fields only the first contribution is found and the second contribution due to electronhole pairs is missed. As noted, in this case the PV current never vanishes simultaneously for all realizations and its RMS value is a monotonic function of the power of the EM radiation [5,6,11,17]. The non-monotonic behavior of the RMS value of the PV current is an indication of the quantum behavior of the EM fields.…”

“…This effect arises in mesoscopic conductors because the phase-coherent transmission through the device almost always violates parity symmetry and the nonequilibrium distribution created by the EM field sets up a steady-state current dictated by this parity violation. When the parity violation is due to random interference, the sign of this current will fluctuate from sample to sample and its rootmean-square (RMS) size in this case depends on the power in the EM field [5,6,8,9,10,11]. Hence after this PV current is calibrated it can be used for detection of the power in the incident EM field.…”

“…When the parity violation is due to random interference, the sign of this current will fluctuate from sample to sample and its rootmean-square (RMS) size in this case depends on the power in the EM field [5,6,8,9,10,11]. Hence after this PV current is calibrated it can be used for detection of the power in the incident EM field.The previous theoretical description [5,6,9,10,11,12] of the PV current has employed a classical treatment of the EM fields, since this description was sufficient for the systems studied experimentally [7,8,13,14,15]. In this case the RMS PV current is a monotonically increasing function of the EM field power.…”

“…In phase-coherent (mesoscopic) devices there are quantum interference effects in electron transport such as the weak localization correction to the conductance and universal conductance fluctuations which can in principle be used to detect radiation since it suppresses these effects [2,3,4]. In practice the suppression of coherent transport by EM fields is difficult to separate from the suppression by intrinsic interactions due to the electron-electron and electron-phonon couplings.A more reliable mean of using mesoscopic conductors to detect EM radiation is to look at the DC current induced by such a field at zero voltage and temperature bias across the device, known as the mesoscopic photovoltaic (PV) effect [5,6,7,8]. This effect arises in mesoscopic conductors because the phase-coherent transmission through the device almost always violates parity symmetry and the nonequilibrium distribution created by the EM field sets up a steady-state current dictated by this parity violation.…”

“…A more reliable mean of using mesoscopic conductors to detect EM radiation is to look at the DC current induced by such a field at zero voltage and temperature bias across the device, known as the mesoscopic photovoltaic (PV) effect [5,6,7,8]. This effect arises in mesoscopic conductors because the phase-coherent transmission through the device almost always violates parity symmetry and the nonequilibrium distribution created by the EM field sets up a steady-state current dictated by this parity violation.…”