scholarly journals Tailoring the phase transition and electron-phonon coupling in 1T′−MoTe2 by charge doping: A Raman study

2020 ◽  
Vol 102 (5) ◽  
Author(s):  
Suvodeep Paul ◽  
Saheb Karak ◽  
Manasi Mandal ◽  
Ankita Ram ◽  
Sourav Marik ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Charge Doping ◽  
Raman Study

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.

scholarly journals Raman study of electron-phonon coupling in thin films of the spinel oxide superconductor LiTi2O4

2017 ◽  
Vol 96 (9) ◽  
Author(s):  
D. Chen ◽  
Y.-L. Jia ◽  
T.-T. Zhang ◽  
Z. Fang ◽  
K. Jin ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxide Superconductor ◽  
Phonon Coupling ◽  
Spinel Oxide ◽  
Electron Phonon Coupling ◽  
Raman Study

Phase-transition induced changes in the electron–phonon coupling of all-trans-β-carotene

2013 ◽  
Vol 104 ◽  
pp. 92-96 ◽  
Author(s):  
Guannan Qu ◽  
Meijiao Sun ◽  
Shuo Li ◽  
Chenglin Sun ◽  
Tianyuan Liu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Induced Changes ◽  
Β Carotene

Raman study of Fano-like electron-phonon coupling in δ-doping GaAs superlattices

1996 ◽  
Vol 54 (19) ◽  
pp. 13927-13931 ◽  
Author(s):  
Yu. A. Pusep ◽  
M. T. O. Silva ◽  
J. C. Galzerani ◽  
S. W. da Silva ◽  
L. M. R. Scolfaro ◽  
...  
Keyword(s):  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Raman Study

scholarly journals A large modulation of electron-phonon coupling and an emergent superconducting dome in doped strong ferroelectrics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiaji Ma ◽  
Ruihan Yang ◽  
Hanghui Chen
Keyword(s):  
Phase Transition ◽  
First Principles ◽  
Critical Concentration ◽  
Phonon Coupling ◽  
Total Electron ◽  
Epitaxial Strain ◽  
Itinerant Electrons ◽  
Weakly Coupled ◽  
Electron Phonon Coupling ◽  
Viable Approach

AbstractWe use first-principles methods to study doped strong ferroelectrics (taking BaTiO3 as a prototype). Here, we find a strong coupling between itinerant electrons and soft polar phonons in doped BaTiO3, contrary to Anderson/Blount’s weakly coupled electron mechanism for "ferroelectric-like metals”. As a consequence, across a polar-to-centrosymmetric phase transition in doped BaTiO3, the total electron-phonon coupling is increased to about 0.6 around the critical concentration, which is sufficient to induce phonon-mediated superconductivity of about 2 K. Lowering the crystal symmetry of doped BaTiO3 by imposing epitaxial strain can further increase the superconducting temperature via a sizable coupling between itinerant electrons and acoustic phonons. Our work demonstrates a viable approach to modulating electron-phonon coupling and inducing phonon-mediated superconductivity in doped strong ferroelectrics and potentially in polar metals. Our results also show that the weakly coupled electron mechanism for "ferroelectric-like metals” is not necessarily present in doped strong ferroelectrics.

scholarly journals Detecting electron-phonon coupling during photoinduced phase transition

2021 ◽  
Vol 103 (12) ◽  
Author(s):  
Takeshi Suzuki ◽  
Yasushi Shinohara ◽  
Yangfan Lu ◽  
Mari Watanabe ◽  
Jiadi Xu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

Pressure-induced phase transition, metallization and superconductivity in ZrS2

2018 ◽  
Vol 20 (36) ◽  
pp. 23656-23663 ◽  
Author(s):  
Hang Zhai ◽  
Zhen Qin ◽  
Dan Sun ◽  
Jianyun Wang ◽  
Chang Liu ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Phonon Coupling ◽  
Band Structures ◽  
Electronic Band ◽  
Electron Phonon Coupling ◽  
Electronic Band Structures ◽  
Stable Structures

The high-pressure thermodynamically stable structures of ZrS2 have been extensively identified using an effective CALYPSO algorithm. Our theoretical electronic band structures and electron–phonon coupling unravel the occurrence of pressure-induced metallization and superconductivity in ZrS2.

Resonant Raman Scattering in CdSxSe1−x Nanocrystals: Electron-Phonon Coupling

1994 ◽  
Vol 358 ◽  
Author(s):  
M. Silvestri ◽  
L.W. Hwang ◽  
P. Persans ◽  
J. Schroeder
Keyword(s):  
Phase Transition ◽  
Raman Scattering ◽  
Coupling Strength ◽  
Phonon Coupling ◽  
Transition Pressure ◽  
Pressure Point ◽  
Phase Transition Pressure ◽  
Electron Phonon Coupling ◽  
Resonant Raman ◽  
Resonant Raman Scattering

ABSTRACTWe report pressure and laser tuned Raman scattering studies on CdSxSei1-x nanocrystals. The electron-phonon coupling strength was determined as a function of pressure beyond the bulk phase transition pressure point. The coupling strength at atmospheric pressure determined from the Stokes shifted photoluminescence and resonant Raman scattering is not drastically smaller than the bulk value as might be expected theoretically. As a function of pressure it also shows no abrupt changes at the bulk phase transition pressure point. These results indicate that deep traps play a critical part in the mechanism of the electron-phonon coupling.

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