Please use this identifier to cite or link to this item:
http//localhost:8080/jspui/handle/123456789/100| Title: | Etude ab initio des Spectres des Phonons et les Propriétés Thermodynamiques des Semi-Conducteurs |
| Authors: | CHAOUCHE, Yassine |
| Issue Date: | 22-Jan-2017 |
| Abstract: | Wehavestudiedthestructural,dynamicalandthermodynamicalpropertiesofYttrium Pnictides YX(X=N,P,AsandSb)inbothphasesB1(NaCl)andB2(CsCl).Weuse¯rst- principles calculations,bymeansofthepseudopotentialmethodusingthegeneralized gradientapproximation(GGA).Wecalculatedstructuralparameters;thelatticeconstant are obtainedbyminimizingtheenergyasfunctionofvolumeandbulkmodulusandits derivativeforYX(X=N,P,AsandSb)compoundsinbothphasesB1andB2.Theyarein goodagreementwiththepublisheddata.wahaveobtainedthetransitionpressure Pt from B1 toB2whentheenthalpyareequalanditisabout171,72,75and34GPaforYN,YP, YAsandYSbcompoundsrespectively.Weevaluatedtheelasticconstants C11,C12 et C44 whichsatisfythemechanicalstabilitiescriteria.DensityFunctionalPerturbationTheory (DFPT) isappliedtodeterminethephonondispersionrelationsalongthehighsymmetry lines withcorrespondingphonondensityofstates.InB1phase,thefrequenciesarepositive valuesthatshowthestabilityofthisstructure.InB2phase,thefrequenciesarenegative valuesthatshowthatthisstructureisunstableat0GPa.Byusingthecalculatedphonon frequencies, weobtainedthethermodynamicproperties;constant-volumespeci¯cheat Cv whichincreasewithtemperatureandapproachesthelimitingDulong-Petit,theentropy S increasewithtemperatureatdi®erentpressures. |
| URI: | http//localhost:8080/jspui/handle/123456789/100 |
| Appears in Collections: | 3.Faculté des Science Exactes et des Sciences de la Nature et de la Vie |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| Etude ab initio des Spectres des Phonons et les Propriétés Thermodynamiques des Semi-Conducteurs.pdf | 1,87 MB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.