Raman spectroscopy of very small Cd1−x Cox S quantum dots grown by a novel protocol: direct observation of acoustic-optical phonon coupling

2013 ◽  
Vol 44 (7) ◽  
pp. 1022-1032 ◽  
Author(s):  
E. S. Freitas Neto ◽  
A. C. A. Silva ◽  
S. W. da Silva ◽  
P. C. Morais ◽  
J. A. Gómez ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Raman Spectroscopy ◽  
Direct Observation ◽  
Optical Phonon ◽  
Phonon Coupling

Charge-Sensitive Surface Optical Phonon in CdS Quantum Dots Studied by Resonant Raman Spectroscopy

2014 ◽  
Vol 118 (51) ◽  
pp. 30269-30273 ◽  
Author(s):  
Yongkuan Wu ◽  
Shaoqing Jin ◽  
Yun Ye ◽  
Shengyang Wang ◽  
Zhaochi Feng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Raman Spectroscopy ◽  
Optical Phonon ◽  
Cds Quantum Dots ◽  
Surface Optical ◽  
Resonant Raman

Confinement induced decrease of the exciton-longitudinal optical phonon coupling in GaN quantum dots

1999 ◽  
Vol 75 (13) ◽  
pp. 1935-1937 ◽  
Author(s):  
Peter Ramvall ◽  
Satoru Tanaka ◽  
Shintaro Nomura ◽  
Philippe Riblet ◽  
Yoshinobu Aoyagi
Keyword(s):  
Quantum Dots ◽  
Optical Phonon ◽  
Longitudinal Optical ◽  
Longitudinal Optical Phonon ◽  
Phonon Coupling

Direct observation of three-photon resonance in water-soluble ZnS quantum dots

2008 ◽  
Vol 92 (13) ◽  
pp. 131114 ◽  
Author(s):  
Jun He ◽  
Gregory D. Scholes ◽  
Yu Long Ang ◽  
Wei Ji ◽  
Cyrus W. J. Beh ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Direct Observation ◽  
Water Soluble ◽  
Photon Resonance

scholarly journals Direct observation of excitonic instability in Ta2NiSe5

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kwangrae Kim ◽  
Hoon Kim ◽  
Jonghwan Kim ◽  
Changil Kwon ◽  
Jun Sung Kim ◽  
...  
Keyword(s):  
Phase Transition ◽  
Direct Observation ◽  
Structural Phase ◽  
Temperature Phase ◽  
Phonon Coupling ◽  
Strong Electron ◽  
Weiss Temperature ◽  
Excitonic Insulator ◽  
Electron Phonon Coupling ◽  
Low Temperature Phase

AbstractCoulomb attraction between electrons and holes in a narrow-gap semiconductor or a semimetal is predicted to lead to an elusive phase of matter dubbed excitonic insulator. However, direct observation of such electronic instability remains extremely rare. Here, we report the observation of incipient divergence in the static excitonic susceptibility of the candidate material Ta2NiSe5 using Raman spectroscopy. Critical fluctuations of the excitonic order parameter give rise to quasi-elastic scattering of B2g symmetry, whose intensity grows inversely with temperature toward the Weiss temperature of TW ≈ 237 K, which is arrested by a structural phase transition driven by an acoustic phonon of the same symmetry at TC = 325 K. Concurrently, a B2g optical phonon becomes heavily damped to the extent that its trace is almost invisible around TC, which manifests a strong electron-phonon coupling that has obscured the identification of the low-temperature phase as an excitonic insulator for more than a decade. Our results unambiguously reveal the electronic origin of the phase transition.

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