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1、西北工业大学工学硕士学位论文IIABSTRACTABSTRACTMonolayerMoS2asthenoveltychannelmaterialoffield-effecttransistorhasbeenattractedtremendousattentionandresearch.Itselectronicandopticalpropertieshavebeenwidelystudied,butthethermalpropertiesofmonolayerMoS2arenotwellunders
2、toodyet.InvestigatingthevibrationalpropertiesandthermalpropertiesofmonolayerMoS2isbeneficialtothestabilityandefficiencyofmonolayerMoS2deviceunderdifferenttemperature.Therefore,thepaper“Firstprinciplecalculationofthelatticevibrationandthermalpropertieso
3、fmonolayerMoS2”isofgreattheoreticalandpracticalsignificance.ThedissertationisdevotedtostudyoflatticevibrationalpropertiesandthermalpropertiesofmonolayerMoS2fromCASTEPsoftandfirstprincipleswithdensityfunctionaltheoryanddensityfunctionalperturbationtheor
4、y.Firstly,thelatticeconstantsandelectronicstructuresofmonolayerMoS2withstrainwerecalculatedinthecaseofconsideringthecalculationaccuracyandcomputationalefficiency.Resultsshowthatthepresentcalculatedresultsareclosetoothertheoreticalandexperimentaldata,su
5、ggestingthatthepresentresearchmethodiscredible.Secondly,thispapercomparativelyinvestigatedthelatticevibrationalpropertiesofmonolayerMoS2,bulkMoS2andmonolayergraphene.AnalysisshowsthatthephonondispersionofmonolayerMoS2andbulkMoS2exhibitsthesamebandgap,b
6、utthenumberofphonondispersionofmonolayerMoS2andbulkMoS2isdifferent.Inaddition,contrasttomonolayerMoS2,thegrüneisenparametersofmonolayerMoS2arepositive.Moreover,thegrüneisenparametersofacousticphononmodesofmonolayerMoS2showasymmetriccharacterinthefirstb
7、rillouinzone,whereasthegrüneisenparametersofopticalphononmodesofmonolayerMoS2showsymmetriccharacterinthefirstbrillouinzone.Besides,thefrequenciesofopticalphononmodesofmonolayerMoS2linearwithbiaxialstrain.Notably,A1modeshowsthelowestchangerate.Finally,t
8、hispaperinvestigatedthethermalpropertiesofmonolayerMoS2.ResultsshowtheDebyetemperature,isochoricspecificheatcapacityandthermalexpansioncoefficientofmonolayerMoS2increasewiththeincreasingtemperature,andthenapproachtofixdataof603K,17.6Cal
