Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 66: Ultrafast Dynamics of Light-Driven Systems
TT 66.7: Vortrag
Freitag, 5. April 2019, 11:30–11:45, H2
Enhancement of superconductivity in MgB2 by narrow-band THz pumping — •Nilabha Bhattacharjee1, Amrit Raj Pokharel1, Tao Dong1,2, Alexej Pashkin3, Stephan Winnerl3, Manfred Helm3, Zi Zhao Gan4, Yue Wang4, Li Yu Shi4, Nan Lin Wang4, and Jure Demsar1 — 1Institute of Physics, Johannes Gutenberg-University Mainz, Mainz — 2International Center For Quantum Materials (ICQM), Peking University — 3Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden — 4Institute of Condensed Matter Physics, School of Physics, Peking University
First observations of amplified superconductivity by electromagnetic radiation at sub-gap frequencies date back to late 1960’s [1]. These works reported an increase of the gap and the superconducting transition temperature in type-I superconductors Al and Sn. Recently, enhancement effects have also been observed in NbN by using picosecond narrow-band THz pulses, tuned to the vicinity of the superconducting gap frequency [2]. Here we report on systematic studies of the superconducting gap dynamics in MgB2. Tuning the pump frequency between the two superconducting gap energies in this two-band superconductor we observe strong superconducting enhancement effects competing with THz driven pair-breaking. For temperatures close to the transition temperature (Tc = 36 K) the enhancement effects seem to dominate, giving rise to a global amplification of superconductivity.
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