نتایج جستجو برای: longitude optical phonon

تعداد نتایج: 282714  

2014
Amit Verma Adam P. Kajdos Tyler A. Cain Susanne Stemmer Debdeep Jena

The temperature dependent Hall mobility data from La-doped SrTiO3 thin films are analyzed and modeled considering various electron scattering mechanisms. We find that a ∼6 meV transverse optical phonon deformation potential scattering mechanism is necessary to explain the dependence of transport on temperature between 10–200 K. Also, we find that the low temperature electron mobility in intrins...

2013
M. Tohidi F. Z. Tohidi

Temperature and doping dependencies of electron mobility in InP semiconductor has been calculated using an iterative technique. The following scattering mechanisms, i.e, impurity, polar optical phonon, acoustic phonon and piezoelectric are included in the calculation. It is found that the electron mobility decreases monotonically as the temperature increases from 100 K to 600 K. The low tempera...

2009
Takami Tohyama Hiroaki Matsueda T. Tohyama H. Matsueda

Interplay of strong electron correlation and electron-phonon interaction is one of important issues in the physics of low dimensional correlated electron systems. In order to understand the interplay, we examine the optical properties of the one-dimensional (1D) Hubbard-Holstein model at half-filling, by employing the dynamical density matrix renormalization group (DMRG) technique. We discuss t...

2011
J. Hernandez-Rueda A. Savoia W. Gawelda J. Solis B. Mansart D. Boschetto J. Siegel

The transient reflectivity response of phase-change Ge2Sb2Te5 films to intense femtosecond laser pulses is studied by ultrafast coherent phonon spectroscopy. The three different phases amorphous, fcc-, and hcp-crystalline , as well as laser-crystallized films, are investigated, featuring different photoexcited carrier and coherent optical phonon dynamics. At least two main phonon frequencies ar...

Journal: :Physical review letters 2012
G De Filippis V Cataudella E A Nowadnick T P Devereaux A S Mishchenko N Nagaosa

The spectral response and physical features of the 2D Hubbard-Holstein model are calculated both in equilibrium at zero and low chemical dopings, and after an ultrashort powerful light pulse, in undoped systems. At equilibrium and at strong charge-lattice couplings, the optical conductivity reveals a three-peak structure in agreement with experimental observations. After an ultrashort pulse and...

2014
H. Alawadhi R. Vogelgesang A. K. Ramdas T. P. Chin J. M. Woodall

The momentum conserving indirect excitonic transitions, from the ⌫ 15 valence band maximum to the conduction band minima close to the X 1 point in the Brillouin zone have been measured for GaP in piezo-modulated transmission. At 6 K, excitonic signatures due to phonon emission are observed at E gx ϩប␻ ph for TA͑X͒, LA͑X͒, and TO͑X͒ phonons ͑E gx ϭfree exciton band gap͒, whereas at 120 K signatures for ...

Journal: :The Journal of chemical physics 2005
S J Xu Shi-Jie Xiong S L Shi

We report on a photoluminescence observation of robust excitonic polarons due to resonant coupling of exciton and longitudinal optical (LO) phonon as well as Fano-type interference in high quality ZnO crystal. At low enough temperatures, resonant coupling of excitons and LO phonons leads to not only traditional Stokes lines (SLs) but also up to second-order anti-Stokes lines (ASLs) besides the ...

1997
C. C. Homes B. P. Clayman J. L. Peng R. L. Greene

The ab-plane reflectance of a Nd 1.85Ce 0.15CuO 4 single crystal (Tc523 K! has been measured from '35 to 9500 cm 21 at temperatures above and below Tc , and the optical properties calculated from a Kramers-Kronig analysis. A rich phonon spectrum is observed, and there are a number of c-axis infrared and Raman modes that are observed at low temperature which are believed to be activated by disor...

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