scholarly journals Light-induced enhancement of superconductivity in iron-based superconductor FeSe0.5Te0.5

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kazuki Isoyama ◽  
Naotaka Yoshikawa ◽  
Kota Katsumi ◽  
Jeremy Wong ◽  
Naoki Shikama ◽  
...  
Keyword(s):  
Thermal Control ◽  
Ultrafast Dynamics ◽  
Light Sources ◽  
Multiple Quantum ◽  
Time Resolved ◽  
Quantum Phases ◽  
Third Harmonic ◽  
Orbital Character ◽  
Common Understanding ◽  
Enhancement Of Superconductivity

AbstractIllumination of light on matter normally causes heating and destroys the ordered ground states. Despite this common understanding, recent advances in ultrafast light sources have enabled the non-thermal control of quantum phases. Here, we report the light-induced enhancement of superconductivity in a thin film of an iron chalcogenide FeSe0.5Te0.5, which exhibits multiple quantum condensates associated with the multi-orbital character. Upon the photoexcitation, we observed a transient increase of the superfluid density as indicated by the optical conductivity in the frequency range of superconducting gaps. The light-induced enhancement of superconductivity is further corroborated by the photoinduced enhancement of terahertz third harmonic generation, which is accounted for by the Higgs mode response. The ultrafast dynamics of two superfluid components revealed by frequency- and time-resolved terahertz measurements indicate the interplay between the condensates through the interband Cooper pairings while suggesting the potential tunability of the pairing interaction by light in the ultrafast timescale.

Ultrafast dynamics of Ni+-irradiated and annealed GaInAs/InP multiple quantum wells

2006 ◽  
Vol 39 (13) ◽  
pp. 2659-2663 ◽  
Author(s):  
V D S Dhaka ◽  
N V Tkachenko ◽  
H Lemmetyinen ◽  
E-M Pavelescu ◽  
S Suomalainen ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Multiple Quantum Wells ◽  
Ultrafast Dynamics ◽  
Multiple Quantum

scholarly journals Development of an experimental apparatus to observe ultrafast phenomena by tender X-ray absorption spectroscopy at PAL-XFEL

2022 ◽  
Vol 29 (1) ◽  
Author(s):  
Yujin Kim ◽  
Daewoong Nam ◽  
Rory Ma ◽  
Sangsoo Kim ◽  
Myung-jin Kim ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Spectroscopic Technique ◽  
Ultrafast Dynamics ◽  
Electronic Information ◽  
Time Resolved ◽  
X Ray ◽  
Experimental Apparatus ◽  
Technical Achievement ◽  
X Ray Absorption ◽  
Pal Xfel

Understanding the ultrafast dynamics of molecules is of fundamental importance. Time-resolved X-ray absorption spectroscopy (TR-XAS) is a powerful spectroscopic technique for unveiling the time-dependent structural and electronic information of molecules that has been widely applied in various fields. Herein, the design and technical achievement of a newly developed experimental apparatus for TR-XAS measurements in the tender X-ray range with X-ray free-electron lasers (XFELs) at the Pohang Accelerator Laboratory XFEL (PAL-XFEL) are described. Femtosecond TR-XAS measurements were conducted at the Ru L 3-edge of well known photosensitizer tris(bipyridine)ruthenium(II) chloride ([Ru(bpy)3]2+) in water. The results indicate ultrafast photoinduced electron transfer from the Ru center to the ligand, which demonstrates that the newly designed setup is applicable for monitoring ultrafast reactions in the femtosecond domain.

Scintillator-Based Nanosecond Light Sources for Time-Resolved Fluorimetry

1995 ◽  
Vol 49 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Steven E. Hobbs ◽  
Gary M. Hieftje
Keyword(s):  
Light Sources ◽  
Time Resolved

scholarly journals Ultrafast dynamics of a bi-stable azopyridine Ni-porphyrin spin switch after photoexcitation in the porphyrin B-bands

2019 ◽  
Vol 205 ◽  
pp. 05019
Author(s):  
Sebastian Megow ◽  
Julia Bahrenburg ◽  
Mark Dittner ◽  
Birthe Kohly ◽  
Joachim Gripp ◽  
...  
Keyword(s):  
High Spin ◽  
Room Temperature ◽  
Ultrafast Dynamics ◽  
Time Resolved ◽  
Spin Switch ◽  
Absorption Measurements

Femtosecond time-resolved absorption measurements of a magnetically bi-stable azopyridine Ni-porphyrin in solution at room temperature show that the photo-induced dynamics are dominated by transient low-spin ⇄ high-spin interconversion involving Ni (d2) and (d, d) states.

scholarly journals Electric Field Distribution in strained p-i-n GaN/InGaN multiple quantum well structures.

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
A.N. Cartwright ◽  
Paul M. Sweeney ◽  
Thomas Prunty ◽  
David P. Bour ◽  
Michael Kneissl
Keyword(s):  
Quantum Well ◽  
Electric Field Distribution ◽  
Theoretical Calculations ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Time Resolved ◽  
Quantum Well Structures ◽  
Piezoelectric Field ◽  
Piezoelectric Fields ◽  
Time Resolved Photoluminescence

The presence of piezoelectric fields within p-i-n GaN/InGaN multiple quantum well structures is discussed. Time integrated and time-resolved photoluminescence measurements and theoretical calculations of the effect of these fields is presented. Furthermore, a description of how these fields influence the carrier dynamics and a discussion of how the piezoelectric field effects the design of GaN/InGaN devices is presented.

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