The mesoscopic photovoltaic effect
Abstract
We have studied a photovoltaic (PV) effect in submicron Au wires and rings in which a dc voltage, $V\sb{dc}$, is generated in response to microwave radiation. The lack of inversion symmetry in these small disordered systems allows for a non-linear response, analogous to a small rectifier, in which $V\sb{dc}$ is proportional to the microwave power. At low temperatures the PV effect exhibits oscillations similar to the quantum interference effects present in the now extensively studied conductance measurements. We have observed pronounced Aharonov-Bohm oscillations of the mesoscopic PV effect in Au rings with diameters ranging from d = 3300-5700 A for temperatures $T\sim 4$ K. The effects of dephasing due to the high frequency (microwave) field have also been observed, where the Aharonov-Bohm oscillations are quenched for microwave field strengths $E\sb{ac}\sim 5.0$ V/m. The suppression of the Aharonov-Bohm oscillations as a function of temperature (T = 14-15 K) was also studied and found to be much weaker than expected. We also report the observation of an anomalous PV signal due to the presence of superconducting contacts which has been attributed to the inverse Josephson effect.
Degree
Ph.D.
Advisors
Giordano, Purdue University.
Subject Area
Condensation|Electromagnetism
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