基底對硅納米線熱導(dǎo)率影響的分子動(dòng)力學(xué)研究

1、中國工程熱物理學(xué)會傳熱傳質(zhì)學(xué)學(xué)術(shù)會議論文編號：103002基底對硅納米線熱導(dǎo)率影響的分子動(dòng)力學(xué)研究王建強(qiáng)12，魏志勇12，畢可東12，陳敏華12，陳云飛123(1東南大學(xué)機(jī)械工程學(xué)院南京210096)(2東南大學(xué)江蘇省微納生物醫(yī)療器械設(shè)計(jì)與制造重點(diǎn)實(shí)驗(yàn)室南京210096)(3東南大學(xué)MEMS教育部重點(diǎn)實(shí)驗(yàn)室南京210096)（Tel:15895863756Email：wjqcc@）摘要：采用非平衡態(tài)分子動(dòng)力學(xué)模擬的方法研究了硅納米線平放

2、在基底上的軸向熱導(dǎo)率，結(jié)果表明基底的存在降低了納米線的熱導(dǎo)率，且隨著溫度的升高，熱導(dǎo)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(qiáng)度，研究了基底約束對硅納米線熱導(dǎo)率的影響，結(jié)果表明，隨著作用力強(qiáng)度的增加，納米線熱導(dǎo)率逐漸減小。模擬結(jié)果還顯示，基底維數(shù)的降低能夠進(jìn)一步減小硅納米線的熱導(dǎo)率。關(guān)鍵詞：軸向熱導(dǎo)率；納米線；基底；分子動(dòng)力學(xué)。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(dòng)力學(xué)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?cái)喟霃?。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?cái)喟霃?，σLJ為平衡常數(shù)，勢阱常數(shù)由文獻(xiàn)[18、19]得到。LJ?系統(tǒng)熱流可以表示為:J(4)()111[()()]26iiijijiijikij