金属纳米线结构中的量子化声子模式及电子—声子相互作用

发布时间：2018-02-12 09:12

本文关键词： 声学声子金属纳米线量子化的声子模式电子-声子相互作用　出处：《云南大学》2015年硕士论文　论文类型：学位论文

【摘要】：纳米科技对电子学、光电子学、材料科学等不同领域有着革命性的影响。纳米结构材料因在力、热、光、电和磁等方面的特性,成为近几十年来研究的热点。目前已能制备各种金属纳米线结构材料,其在光电子器件和超声器件中具有重要的应用价值。晶格振动的能量量子称为声子,量子化的声子对纳米结构材料中的电子的输运和热传导起着决定性的作用,材料的很多物理性质受声子模式以及电子声子交互作用的影响,所以声子一直是凝聚态物理学和电子学领域的重要研究对象。本文主要研究了以氧化铝为模板制备的金属纳米线结构中的声学声子模式、电子子带能级结构、电子与声子间的相互作用以及声学声子激发谱。改变金属纳米线的半径、模板半径,研究不同量子数m、v下的声学声子模式的变化,电子与声子间的相互作用的强弱及声子模式的激发谱特征；改变系统温度,研究电子与声子间的相互作用强弱及声学声子模式的激发谱特征。利用柱形纳米线结构来描述以氧化铝为模板制备的金属铜纳米线。考虑器件结构中弹性声波对应的边界及连续性条件,求解弹性波波动方程,可以得到金属纳米线结构中的量子化声学声子模式。在此基础上,我们研究了金属纳米线结构中的电子-声子相互作用及声子激发谱。本文的研究内容对金属纳米线系统在高频超声器件中的应用有着重要的意义。通过系统的理论研究,我们得出了一下结论： (1)声子波矢较小时,金属纳米线结构中不存在声学声子模式。当声子波矢增大到一定数值时,金属纳米线结构中开始存在一系列不同的声学声子振动模式。 (2)金属纳米线结构中的声子波矢和声子频率近似为线性关系,且声子频率随着声子波矢的增大而增大。 (3)影响纳米线结构中的量子化声子模式的主要因素为金属纳米线半径r0,而纳米线模板半径不影响声子的色散关系。 (4)金属纳米线结构中的电子与声子的交互作用主要受系统温度、纳米线半径ro、电子态和声子态的影响。 (5)金属纳米线结构中的声学声子激发谱受系统温度和纳米线半径的影响。系统温度越高,通过电子-声子交互作用引起的声学声子的激发越强,金属纳米线的半径越小,声学声子的激发越强。
[Abstract]:Nanotechnology has revolutionized the fields of electronics, optoelectronics, material science, etc. Nanostructured materials are characterized by force, heat, light, electricity and magnetism. It has been widely used in photoelectron devices and ultrasonic devices. The energy quantum of lattice vibration is called phonon. Quantized phonons play a decisive role in the transport and heat conduction of electrons in nanostructured materials. Many of the physical properties of the materials are affected by phonon modes and electronic phonon interactions. Therefore, phonon has been an important research object in condensed matter physics and electronics. In this paper, the acoustic phonon mode, the energy level structure of electron subband, the interaction between electron and phonon, the excitation spectrum of acoustic phonon and the radius of metal nanowire are studied. Template radius, the variation of acoustic phonon modes at different quantum numbers mv, the intensity of the interaction between electrons and phonons and the characteristics of excitation spectrum of phonon modes, the change of system temperature, The intensity of interaction between electron and phonon and the excitation spectrum of acoustic phonon mode are studied. A columnar nanowire structure is used to describe the copper nanowires prepared by aluminum oxide template. The elastic acoustic pair in the device structure is considered. Boundary and continuity conditions, The quantized acoustic phonon modes in metal nanowire structures can be obtained by solving the wave equation of elastic waves. We have studied the electron-phonon interaction and phonon excitation spectra in metal nanowire structures. The research in this paper is of great significance to the application of metal nanowire systems in high-frequency ultrasonic devices. Through the systematic theoretical research, we draw a conclusion:. 1) when the phonon wave vector is small, there is no acoustic phonon mode in the metal nanowire structure. When the phonon wave vector increases to a certain value, there are a series of different acoustic phonon vibration modes in the metal nanowire structure. 2) the phonon wave vector and the phonon frequency in the metal nanowire structure are approximately linear, and the phonon frequency increases with the increase of the phonon wave vector. The main factor affecting the quantized phonon mode in nanowire structure is metal nanowire radius r _ 0, while the nanowire template radius does not affect the dispersion relationship of phonons. The interaction between electron and phonon in metal nanowire structure is mainly affected by system temperature, radius roof nanowire, electronic state and phonon state. 5) the acoustic phonon excitation spectrum in the metal nanowire structure is affected by the system temperature and nanowire radius. The higher the system temperature, the stronger the acoustic phonon excitation caused by electron-phonon interaction, and the smaller the metal nanowire radius. The stronger the acoustic phonon is.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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