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TT: Fachverband Tiefe Temperaturen
TT 92: Transport – Poster
TT 92.11: Poster
Donnerstag, 12. März 2026, 18:00–20:00, P4
Photogalvanic Effect as a Probe for Distinguishing type-I and type-II Semi-Dirac Systems — •Bristi Ghosh1, Malay Bandyopadhyay1, and Snehasish Nandy2 — 1Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 752050, India — 2National Institute of Technology Silchar, Assam, 788010, India
The photogalvanic effect (PGE) generates a direct photocurrent under polarized light in non-centrosymmetric systems, manifesting as the linear photogalvanic effect (LPGE) or circular photogalvanic effect (CPGE) depending on light polarization. Using quantum kinetic theory within the relaxation-time approximation, we theoretically explore the PGE as a probe of quantum geometry in anisotropic type-I and type-II semi-Dirac (SD) systems. The PGE conductivity, comprising injection, shift, resonant, higher-order pole, and anomalous contributions, exhibits a pronounced enhancement in type-II systems compared to type-I. For the CPGE, both anomalous and resonant terms, arising from Fermi surface contributions, decrease with increasing chemical potential in type-I but increase in type-II systems. For the LPGE, the xxx-component of the shift conductivity in type-II SD reverses sign upon tuning the gap tuning parameter δ, while other components remain invariant, similar to type-I behavior. These contrasting CPGE and LPGE responses provide clear optical signatures distinguishing the two SD phases. The predicted effects, potentially realizable in TiO2/VO2 heterostructures, establish the PGE as a sensitive probe of quantum geometry and a promising route toward next-generation optoelectronic applications.
Keywords: Photogalvanic Effect; Semi-Dirac; Quantum Geometry; CPGE and LPGE; Type-I and Type-II Phase Distinction