Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 33: Optical Properties 2
HL 33.2: Vortrag
Donnerstag, 8. September 2022, 15:15–15:30, H32
The Berry dipole photovoltaic demon and the thermodynamics of photo-current generation within the optical gap of metals — Li-kun Shi1, Oles Matsyshyn2,1, Justin C. W. Song2, and •Inti Sodemann Villadiego3,1 — 1Max-Planck-Institut fur Physik komplexer Systeme — 2Division of Physics and Applied Physics, Nanyang Technological University, Singapore — 3Institut fur Theoretische Physik, Universitat Leipzig
Berry phase driven photo-voltaic effects offer novel mechanisms that could allow to engineer a new generation of opto-electronic technologies.
We will show that there is a large class of bulk photovoltaic mechanisms that make possible to produce a net rectified photo-voltaic current even when the impinging radiation has a frequency that resides within the optical gap of the material, in contrast to previous claims. We will describe the thermodynamics of these in-gap rectification effects and show that most of these mechanisms are necessarily accompanied by a small but finite irreversible photon absorption in order for them to be consistent with the laws of thermodynamics. There is, however, one remarkable exception: the intra-band non-linear Hall effect arising from the anomalous velocity induced by the Berry curvature. This non-linear Hall effect allows to have a photovoltaic mechanisms whose maximum allowed efficiency can be 100% for the conversion of circularly polarized light onto electricity. More remarkably, because it is a reversible process, this same mechanism can be conversely used as a a highly efficient electrical amplifier of circularly polarized light.