含非均匀结构量子波导中6支振动模中的声子输运和热导  

Acoustic phonon transport and thermal conductance associated with six types of vibration modes in quantum waveguide modulated with unsymmetrical structure

作　　者：龚志强[1] 罗勇锋[1,2] 贺梦冬[1] 

机构地区：[1]中南林业科技大学数学物理研究所,湖南长沙410004 [2]中南大学粉末冶金研究院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2012年第3期918-925,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(11174372)

摘　　要：利用散射矩阵方法,研究非均匀结构调制的半导体量子波导中6支最低弹性声子模的输运系数与热导性质。研究结果表明:当4支最低声学声子模的截止频率为0Hz且当频率接近于0Hz时,透射系数总为1;当2支光学模的截止频率大于0Hz且当频率接近截止频率时,透射系数总为0;声子模的输运系数、量子化热导平台以及热导性质与量子点的结构密切相关;在极低温度下,扭转模的热导对结构最敏感,而随着温度的增大,压缩模与y方向的弯曲声学模的热导对量子点的结构最敏感;改变量子点的结构能有效调节6支单模的热导。By using scattering matrix method, the acoustic phonon transport and thermal conductance associated with the six low-lying vibration modes were studied in quantum waveguide modulated with quantum dot. The results show that the cutoff frequency for the four types of acoustic modes is 0 Hz, while two types of optical modes are of nonzero cutoff frequency. The quantized thermal conductance plateau and the thermal conductance property of the single vibration mode related closely with the structure parameter of the waveguide and unsymmetrical structure and the thermal conductance of the different vibration modes show different characteristics. At very low temperatures, the thermal conductance of torsional mode is the most sensitive to the structural parameter. However, at very low temperatures, with the increase of temperature, the thermal conductance of the dilatational mode and the flexural mode iny direction is the most sensitive to the structural parameter. The thermal conductance of the single vibration mode can be adjusted by changing the structure parameter of quantum dot.

关 键 词：非均匀结构 弹性波 声学声子输运 热导 

分 类 号：O426.5[理学—声学]