Contrasting temperature dependence of the band gap in CH3NH3PbX3 (X=I, Br, Cl) : Insight from lattice dilation and electron-phonon coupling

2020 ◽  
Vol 102 (8) ◽  
Author(s):  
Rishabh Saxena ◽  
Jiban Kangsabanik ◽  
Ayush Kumar ◽  
Aga Shahee ◽  
Shivam Singh ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Band Gap ◽  
Phonon Coupling ◽  
Electron Phonon Coupling ◽  
Lattice Dilation

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

Disentangling Electron–Phonon Coupling and Thermal Expansion Effects in the Band Gap Renormalization of Perovskite Nanocrystals

2020 ◽  
pp. 569-575
Author(s):  
Andrea Rubino ◽  
Adrián Francisco-López ◽  
Alex J. Barker ◽  
Annamaria Petrozza ◽  
Mauricio E. Calvo ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Band Gap ◽  
Phonon Coupling ◽  
Perovskite Nanocrystals ◽  
Electron Phonon Coupling

scholarly journals The effect of strong electron-rattling phonon coupling on some superconducting properties

2019 ◽  
Vol 97 (5) ◽  
pp. 472-476
Author(s):  
Samin Tajik ◽  
Božidar Mitrović ◽  
Frank Marsiglio
Keyword(s):  
Temperature Dependence ◽  
Coupling Parameter ◽  
Nmr Relaxation ◽  
Superconducting Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Strong Electron ◽  
Particle Decay ◽  
Electron Phonon Coupling ◽  
The One

Using the Eliashberg theory of superconductivity we have examined several properties of a model in which electrons are coupled only to rattling phonon modes represented by a sharp peak in the electron–phonon coupling function. Our choice of parameters was guided by experiments on β-pyrochlore oxide superconductor KOs2Os6. We have calculated the temperature dependence of the superconducting gap edge; the quasi-particle decay rate; the NMR relaxation rate assuming that the coupling between the nuclear spins and the conduction electrons is via a contact hyperfine interaction, which would be appropriate for the O-site in KOs2Os6; and the microwave conductivity. We examined the limit of very strong coupling by considering three values of the electron–phonon coupling parameter λ = 2.38, 3, and 5 and did not assume that the rattler frequency Ω0 is temperature dependent in the superconducting state. We obtained a very unusual temperature dependence of the superconducting gap edge Δ(T), very much like the one extracted from photoemission experiments on KOs2O6.

The temperature dependence of vibronic lineshapes: Linear electron-phonon coupling

2014 ◽  
Vol 141 (15) ◽  
pp. 154110 ◽  
Author(s):  
Claudia Roos ◽  
Andreas Köhn ◽  
Jürgen Gauss ◽  
Gregor Diezemann
Keyword(s):  
Temperature Dependence ◽  
Linear Electron ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

From 0D Cs3Bi2I9 to 2D Cs3Bi2I6Cl3: Dimensional Expansion Induces a Direct Band Gap but Enhances Electron–Phonon Coupling

2019 ◽  
Vol 31 (7) ◽  
pp. 2644-2650 ◽  
Author(s):  
Kyle M. McCall ◽  
Constantinos C. Stoumpos ◽  
Oleg Y. Kontsevoi ◽  
Grant C. B. Alexander ◽  
Bruce W. Wessels ◽  
...  
Keyword(s):  
Band Gap ◽  
Phonon Coupling ◽  
Direct Band Gap ◽  
Electron Phonon Coupling ◽  
Direct Band

scholarly journals Accurate Model for Temperature Dependence of Solar Cell Performance According to Phonon Energy Correction

2018 ◽  
Vol 55 (5) ◽  
pp. 15-25 ◽  
Author(s):  
Y. Tiandho ◽  
W. Sunanda ◽  
F. Afriani ◽  
A. Indriawati ◽  
T. P. Handayani
Keyword(s):  
Solar Cell ◽  
Temperature Dependence ◽  
Cell Performance ◽  
Bandgap Energy ◽  
Phonon Coupling ◽  
Solar Cell Performance ◽  
Coupling Interaction ◽  
Electron Phonon Coupling ◽  
Increasing Temperature ◽  
Electron Phonon Coupling Interaction

Abstract In many experiments, it has been reported that the performance of solar cells decreases with increasing temperature. This effect arises due to an increase in the intrinsic carrier concentration of material that directly affects the reverse saturation currents (J0). As a result, the open circuit voltage which is inversely proportional to J0 will decrease quite rapidly with increasing temperature. The intrinsic carrier concentration is determined by the bandgap energy of a material and its temperature. The Varshni relationship is a relation for the variation of the bandgap energy with temperature in semiconductors that has been used extensively in the model of a solar cell performance. But the problem is the Varshni relation just calculates the contribution of the vibrational part at the temperature, which is much greater than the Debye temperature. These works proposed a model of temperature dependence of solar cell performance that involves phonon energy correction and electron-phonon coupling interaction. This correction is applied because the electron-phonon coupling interaction is an intrinsic interaction of semiconductors. The existence of interaction cannot be avoided either experimentally or theoretically. The proposed model is compared with experimental data, which have fairly high accuracy.

scholarly journals Ultrafast lattice dynamics in lead selenide quantum dot

2019 ◽  
Vol 205 ◽  
pp. 04017
Author(s):  
Xuan Wang ◽  
Matthew Gorflen ◽  
Jianming Cao
Keyword(s):  
Quantum Dots ◽  
Electron Diffraction ◽  
Femtosecond Laser ◽  
Heat Transport ◽  
Lattice Dynamics ◽  
Phonon Coupling ◽  
Ultrafast Electron Diffraction ◽  
Phonon Bottleneck ◽  
Electron Phonon Coupling ◽  
Lattice Dilation

We monitored the femtosecond-laser-induced lattice dynamics in PbSe quantum dots by ultrafast electron diffraction. The electron-phonon coupling didn’t show phonon bottleneck. And lattice dilation exhibited unusual features. Heat transport to the substrate deviated significantly from Fourier’s Law.

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