Physics - The Anthony J Leggett Institute for Condensed Matter Theory Seminar

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The Anthony J Leggett Institute for Condensed Matter Physics Seminar: Wave Function Geometry for Bulk Photovoltaics

Event Type
Seminar/Symposium
Sponsor
Physics Department
Location
ESB 190
Date
Nov 4, 2024   12:00 pm  
Speaker
Aris Alexandradinata, University of California San Diego
Contact
Ljubica Milutinovic
E-Mail
ljubicam@illinois.edu
Phone
217-300-6393
Views
9

Steady illumination of a non-centrosymmetric semiconductor results in a bulk photovoltaic current, which is contributed by real-space displacements ('shifts') of charged quasiparticles as they transit between Bloch states. The shift induced by interband excitation via absorption of photons has received the prevailing attention. However, this excitation-induced shift can be far outweighed by the shifts induced by intraband relaxation and interband recombination, owing to: (i) an anomalous shift of quasiparticles as they scatter with phonons, as well as to (ii) topological singularities of the interband Berry phase. Both (i) and (ii) make the photocurrent extraordinarily sensitive to the frequency and polarization of the light source, and potentially lead to large non-linear conductivities of order mA/V^2 without experimental fine-tuning. A case study of BiTeI showcases these effects in a realistic material. 

 

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