1、中國工程熱物理學會傳熱傳質(zhì)學學術(shù)會議論文編號：103002基底對硅納米線熱導率影響的分子動力學研究王建強12，魏志勇12，畢可東12，陳敏華12，陳云飛123(1東南大學機械工程學院南京210096)(2東南大學江蘇省微納生物醫(yī)療器械設(shè)計與制造重點實驗室南京210096)(3東南大學MEMS教育部重點實驗室南京210096)（Tel:15895863756Email：wjqcc@）摘要：采用非平衡態(tài)分子動力學模擬的方法研究了硅納米線平放
2、在基底上的軸向熱導率，結(jié)果表明基底的存在降低了納米線的熱導率，且隨著溫度的升高，熱導率逐漸降低。通過改變納米線與基底之間的范德華作用力強度，研究了基底約束對硅納米線熱導率的影響，結(jié)果表明，隨著作用力強度的增加，納米線熱導率逐漸減小。模擬結(jié)果還顯示，基底維數(shù)的降低能夠進一步減小硅納米線的熱導率。關(guān)鍵詞：軸向熱導率；納米線；基底；分子動力學。Moleculardynamicssimulationoftheeffectsofsubstrate
3、onthethermalconductivityofsiliconnanowireWangJianqiang12WeiZhiyong12BiKedong12ChenMinhua12ChenYunfei123(1SchoolofMechanicalEngineeringSoutheastUniversityNanjing210096)(2JiangsuKeyLabatyfDesignManufactureofMicroNanoBiomed
4、icalInstrumentsSoutheastUniversityNanjing210096)(3MEMSKeyLabatyofChinaEducationalMinistrySoutheastUniversityNanjing210096)Abstract:Thelongitudinalthermalconductivityofsiliconnanowireonsubstrateisinvestigatedbynonequilibr
5、iummoleculardynamicssimulations(NEMD).Theresultsshowthatthepresenceofthesubstratelowersthethermalconductivityofsiliconnanowirethethermalconductivitydecreaseswiththeincreasingtemperature.Theeffectsofthesubstrateonthetherm
6、alconductivityofsiliconnanowirearealsoexpledbychangingthestrengthofvanderWaalsinteractionbetweensubstratenanowire.Itdemonstratesthatthethermalconductivityofnanowiredecreaseswiththeincreaseofinteractionstrength.Thepresent
7、studyalsoshowsthatloweringthedimensionofsubstrateleadstoareductioninthethermalconductivityofsiliconnanowireonit.Keywds:longitudinalthermalconductivitynanowiresubstratemoleculardynamics______________________________一種多體作用
8、勢，包括兩體和三體作用力，其形式分別如式(1)、(2)：圖1硅納米線在基底上分子動力學模型(1)()2[()()]()()0()ijcrrpqijcijijijijcABerrrrurrr????????????????(2)[()()]231(cos())()()30()ijcikcrrrrjikijikcijikijikcerrrurrrrr????????????????????????式中為勢阱常數(shù)，σ為平衡常數(shù)，rij為粒子i
9、與j的空間間距，rik為粒子i與k的空?間間距，θjik為rij、rik的夾角，rc為勢能的截斷半徑。納米線與基底之間采用LJ勢描述。LJ勢可表示為：(3)612114[()()]()0LJLJLJijLJcijijLJijijLJcrrrrurrr???????????????其中rc1為截斷半徑，σLJ為平衡常數(shù)，勢阱常數(shù)由文獻[18、19]得到。LJ?系統(tǒng)熱流可以表示為:J(4)()111[()()]26iiijijiijikij