SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: THz and MIR physics in semiconductors
HL 17.1: Vortrag
Dienstag, 28. März 2023, 09:30–09:45, JAN 0027
Terahertz-induced anomalous currents after optical excitation of excitons in quantum wells — •Cong Ngo1, Shekhar Priyadarshi2, Huynh Thanh Duc3, Mark Bieler2, and Torsten Meier1 — 1Department of Physics, Paderborn University, Warburger Strasse 100, D-33098 Paderborn, Germany — 2Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany — 3Institute of Applied Mechanics and Informatics, VAST, 1 Mac Dinh Chi, District 1, Ho Chi Minh City, Vietnam
We study transient anomalous currents in GaAs quantum wells by solving the multi-band semiconductor Bloch equations in the length gauge, including excitonic effects and carrier longitudinal-optical and acoustic phonons scattering process. The band structure is obtained by diagonalizing a 14-band k·p model within the envelope function approximation. To solve the random phase problem originating from the numerical diagonalization of the band structure model, we apply a smoothing gauge transformation [1]. Our numerical results show quite strong anomalous currents appear for optical excitation near the excitonic resonances and simultaneous Terahertz excitation. The current transients oscillate with a frequency corresponding to the inverse of the energy difference between the 1s and 2s exciton states. The numerical results including excitons are in good agreement with experiments [2].
[1] L. H. Thong, C. Ngo, H. T. Duc, X. Song, and T. Meier, Phys. Rev. B 103, 085201 (2021).
[2] S. Priyadarshi, K. Pierz, and M. Bieler, Phys. Rev. Lett. 115, 257401 (2015).