热流对超晶格结构热传导影响的分子动力学研究
|
摘要
超晶格材料的传热性能对其在热电设备、微电子以及光电子等领域的应用起决定性作用。本文采用非平衡态分子动力学方法研究了热流对超晶格结构热导率的影响。利用Tersoff势函数描述超晶格结构中Si粒子与Ge粒子的相互作用,建立了Si/Ge超晶格结构的稳态导热模型。通过分析热流方向上系统内部的温度分布,得出超晶格结构所施加热流的大小和方向都对热导率产生重大影响。研究结果表明:超晶格结构热导率随热流的增大而增大,并且当热流及温度升高到一定程度,超晶格结构可能会发生非傅里叶热传导现象;热流由Si薄膜流向Ge薄膜时超晶格结构热导率大于由Ge薄膜流向Si薄膜时的热导率。
The heat transfer performances of superlattice structure materials play a crucial role in several applications,including thermoelectrics,microelectronics,and optoelectronics. In this study,the effects of heat flux on the thermal conductivity of a superlattice structure were researched by nonequilibrium molecular dynamics simulation.Tersoff potential function was employed to describe the interaction between Si and Ge particles in a superlattice structure. A steady heat transfer simulation model adapted to the Si/Ge superlattice structure was framed. The values and directions of heat flux exerted by the Si/Ge superlattice structure greatly affected the thermal conductivity based on the investigation on the temperature profile along the direction of heat flux. The simulative results indicate that the thermal conductivity increased with the increase in heat flux. In addition,the non-Fourier thermal conductance may occur under large heat flux and temperature. The thermal conductivity of the Si→Ge system was larger than that of the Ge→Si system.
The heat transfer performances of superlattice structure materials play a crucial role in several applications,including thermoelectrics,microelectronics,and optoelectronics. In this study,the effects of heat flux on the thermal conductivity of a superlattice structure were researched by nonequilibrium molecular dynamics simulation.Tersoff potential function was employed to describe the interaction between Si and Ge particles in a superlattice structure. A steady heat transfer simulation model adapted to the Si/Ge superlattice structure was framed. The values and directions of heat flux exerted by the Si/Ge superlattice structure greatly affected the thermal conductivity based on the investigation on the temperature profile along the direction of heat flux. The simulative results indicate that the thermal conductivity increased with the increase in heat flux. In addition,the non-Fourier thermal conductance may occur under large heat flux and temperature. The thermal conductivity of the Si→Ge system was larger than that of the Ge→Si system.
引文
[1]恩克.固体物理基础[M].呼河浩特:内蒙古教育出版社,1993:21-34.
[2]YANG F,LKEDA T,SNYDER G J.Effective thermal conductivity of polycrystallin materials with randomly oriented superlattice grains[J].Journal of applied physics,2010,108(3):034310-034315.
[3]KOH Y K,CAO Y,AHILLD G C,et al.Heat-transport mechanisms in superlattices[J].Advanced functional materials,2009,19(4):610-615.
[4]冯媛,梁新刚,鞠生宏.基于串联模型的Si/Ge超晶格法向热导率[J].工程热物理学报,2013,34(9):1707-1710.FENG Yuan,LIANG Xingang,JU Shenghong.The out-of plane thermal conductivity of Si/Ge superlattice based on the serious model[J].Journal of engineering thermophysics,2013,34(9):1707-1710.
[5]GARG J,CHEN G.Minimum thermal conductivity in superlattices:A first-principles formalism[J].Physical review B condensed matter,2013,87(14):93-96.
[6]HU M,POULIKAKOS D.Si/Ge superlattice nanowires with ultralow thermal conductivity[J].Nano letters,2012,12(11):5487-5494.
[7]LI X B,YANG R G.Equilibrium molecular dynamics simulations for the thermal conductivity of Si/Ge nanocomposites[J].Journal of applied physics,2013,113:104306.
[8]TERSOFF J.New empirical approach for the structure and energy of covalent systems[J].Physical review B,1988,37:6991-7000.
[9]JUND P,JULLIEN R.Molecular dynamics calculation of the thermal conductivity of vitreous silica[J].Physical review B,1999,59:13707-13704.
[10]CHEN Y,LI D,YANG J,et al.Molecular dynamics study of the lattice thermal conductivity of Kr/Ar superlattice nanowires[J].Physical review B,2004,349:270-280.
[11]LANDRY E S,GAUGHEY M.Thermal boundary resistance predictions from molecular dynamics simulations and theoretical calculations[J].Physical review B,2009,80:165304-165309.
[12]FENG Y,LIANG X G,SHENG H J.The out-of-plane thermal conductivity of Si/Ge superlattice based on the serious model[J].Journal of engineering thermophysics,2013,34(9):1707-1710.
[13]吴国强,孔宪仁,孙兆伟,等.单晶硅薄膜法向热导率的分子动力学模[J].哈尔滨工业大学学报,2007,39(9):1366-1369.WU Guoqiang,KONG Xianren,SUN Zhaowei,et al.Molecular dynamics smiulation on the out-of plane thermal conductivity of single-crystal silicon thin films[J].Journal of Harbin Institute of Technology,2007,39(9):1366-1369.
[14]张兴丽,孙兆伟,孔宪仁,等.单晶锗薄膜热导率的分子动力学模拟[J].稀有金属材料与工程,2010,39(5):853-856.ZHANG Xingli,SUN Zhaowei,KONG Xianren,et al.Molecular dynamics simulation of thermal conductivity of germanium thin films[J].Rare metal materials and engineering,2010,39(5):853-856.
[15]RAMIN A,GUILLAUME A,JEAN F M.Impact of internal crystalline boundaries on lattice thermal conductivity:Importance of boundary structure and spacing[J].Applied physics letters,2014,105:194102.
[2]YANG F,LKEDA T,SNYDER G J.Effective thermal conductivity of polycrystallin materials with randomly oriented superlattice grains[J].Journal of applied physics,2010,108(3):034310-034315.
[3]KOH Y K,CAO Y,AHILLD G C,et al.Heat-transport mechanisms in superlattices[J].Advanced functional materials,2009,19(4):610-615.
[4]冯媛,梁新刚,鞠生宏.基于串联模型的Si/Ge超晶格法向热导率[J].工程热物理学报,2013,34(9):1707-1710.FENG Yuan,LIANG Xingang,JU Shenghong.The out-of plane thermal conductivity of Si/Ge superlattice based on the serious model[J].Journal of engineering thermophysics,2013,34(9):1707-1710.
[5]GARG J,CHEN G.Minimum thermal conductivity in superlattices:A first-principles formalism[J].Physical review B condensed matter,2013,87(14):93-96.
[6]HU M,POULIKAKOS D.Si/Ge superlattice nanowires with ultralow thermal conductivity[J].Nano letters,2012,12(11):5487-5494.
[7]LI X B,YANG R G.Equilibrium molecular dynamics simulations for the thermal conductivity of Si/Ge nanocomposites[J].Journal of applied physics,2013,113:104306.
[8]TERSOFF J.New empirical approach for the structure and energy of covalent systems[J].Physical review B,1988,37:6991-7000.
[9]JUND P,JULLIEN R.Molecular dynamics calculation of the thermal conductivity of vitreous silica[J].Physical review B,1999,59:13707-13704.
[10]CHEN Y,LI D,YANG J,et al.Molecular dynamics study of the lattice thermal conductivity of Kr/Ar superlattice nanowires[J].Physical review B,2004,349:270-280.
[11]LANDRY E S,GAUGHEY M.Thermal boundary resistance predictions from molecular dynamics simulations and theoretical calculations[J].Physical review B,2009,80:165304-165309.
[12]FENG Y,LIANG X G,SHENG H J.The out-of-plane thermal conductivity of Si/Ge superlattice based on the serious model[J].Journal of engineering thermophysics,2013,34(9):1707-1710.
[13]吴国强,孔宪仁,孙兆伟,等.单晶硅薄膜法向热导率的分子动力学模[J].哈尔滨工业大学学报,2007,39(9):1366-1369.WU Guoqiang,KONG Xianren,SUN Zhaowei,et al.Molecular dynamics smiulation on the out-of plane thermal conductivity of single-crystal silicon thin films[J].Journal of Harbin Institute of Technology,2007,39(9):1366-1369.
[14]张兴丽,孙兆伟,孔宪仁,等.单晶锗薄膜热导率的分子动力学模拟[J].稀有金属材料与工程,2010,39(5):853-856.ZHANG Xingli,SUN Zhaowei,KONG Xianren,et al.Molecular dynamics simulation of thermal conductivity of germanium thin films[J].Rare metal materials and engineering,2010,39(5):853-856.
[15]RAMIN A,GUILLAUME A,JEAN F M.Impact of internal crystalline boundaries on lattice thermal conductivity:Importance of boundary structure and spacing[J].Applied physics letters,2014,105:194102.