Temperature dependent band gap shrinkage in GaN: Role of electron–phonon interaction

2009 ◽  
Vol 149 (31-32) ◽  
pp. 1288-1291 ◽  
Author(s):  
Niladri Sarkar ◽  
Subhasis Ghosh
2011 ◽  
Vol 406 (14) ◽  
pp. 2847-2850 ◽  
Author(s):  
Bimal Kumar Sarkar ◽  
Ajay Singh Verma ◽  
P.S. Deviprasad

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Mingming Yang ◽  
Longlong Wang ◽  
Xiaofen Qiao ◽  
Yi Liu ◽  
Yufan Liu ◽  
...  

Abstract The defects into the hexagonal network of a sp2-hybridized carbon atom have been demonstrated to have a significant influence on intrinsic properties of graphene systems. In this paper, we presented a study of temperature-dependent Raman spectra of G peak and D’ band at low temperatures from 78 to 318 K in defective monolayer to few-layer graphene induced by ion C+ bombardment under the determination of vacancy uniformity. Defects lead to the increase of the negative temperature coefficient of G peak, with a value almost identical to that of D’ band. However, the variation of frequency and linewidth of G peak with layer number is contrary to D’ band. It derives from the related electron-phonon interaction in G and D’ phonon in the disorder-induced Raman scattering process. Our results are helpful to understand the mechanism of temperature-dependent phonons in graphene-based materials and provide valuable information on thermal properties of defects for the application of graphene-based devices.


2014 ◽  
Vol 446 ◽  
pp. 85-91 ◽  
Author(s):  
A. Mogulkoc ◽  
M. Modarresi ◽  
B.S. Kandemir ◽  
M.R. Roknabadi ◽  
N. Shahtahmasebi ◽  
...  

2002 ◽  
Vol 16 (23) ◽  
pp. 3465-3471
Author(s):  
I. CHAUDHURI ◽  
S. K. GHATAK

The pseudogap structure in low energy excitation in cuprates appears below a temperature and the spectral density exhibits strong wave-vector dependence. An electronic model that emphasized the coupling of carrier in Cu-O with phonon is examined for pseudogap. The electron–phonon interaction originates from the modulation of on-site and hopping energy and leads to spontaneous Jahn–Teller-like distortion and pseudogap below a critical temperature. At low temperature the spectral density has two-peak structure about the Fermi level for all k along Γ-M whereas such structure exists along Γ-X for small k only. The magnitude of pseudogap shows strong k-dependence — maximum along Γ-M and vanishes along Γ-X. These features emphasize the role of electron–phonon interaction in formation of pseudogap.


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