固体物理导论-4

1、Great Experimentalist http:/ http:/ What we can learn from them:The method/design of experiments Todays Outline Photon （光子） Phonon （声子）Lets talk about LightGod said, Let there be light; and there was lightFor a physicist 詹姆斯詹姆斯克拉克克拉克麦克斯韦麦克斯韦 James Clerk Maxwell 18311879 从牛顿到爱因斯坦这一整个阶段中最伟大的理论物理学家 建立了

2、麦克斯韦方程组 创立了经典电磁学 预言了电磁波的存在 提出了光的电磁说 运用数学工具分析物理问题和精确地表述科学思想的大师Light is Electromagnetic Wave“麦克斯韦在潜心研究了法拉第关于电磁学方面的新理论和思想之后，坚信法拉第的新理论包含着真理。于是他抱着给法拉第的理论“提供数学方法基础”的愿望，决心把法拉第的天才思想以清晰准确的数学形式表示出来。” 1888年德国物理学家赫兹用实验验证了电磁波的存在Solar SpectrumPhotoelectric Effect材料 铯钠 锌 银铂 极限波长 652nm540nm 372nm 260nm 196nm Work F

3、unction （电子溢出功）Evacuum EF, work function波粒二象性（wave-particle duality） Radiation Quantization Quantized Radiation: Photon h:普朗克常数(6.626 x 1034 Js) 红光：650nm，1.97 eVE=h = c / Photo-excitation / Radiation excitation Radiative/Non-radiative RecombinationPhoto-Electron interaction Photo generation Fundamen

4、tals for photo detectors and solar cells Radiative recombination Fundamentals for Light Emitting Diodes (LED) and Lasers Break!Phonon Quantized lattice vibration Atomic vibration at room temperature: 1 Vibration has different modes: Phonon modes Energy of phonons: E=hDensity of State function for el

5、ectronsDispersion Relation: density of phonon modes Different phonon modesLA: longitudinal acoustic TA: Transverse acousticLO: longitudinal optical TO: Transverse optical E=h Phonon-Photon interactionEmission of photon, thermal radiationAbsorption of photon, heating of lattice Theories not clear Phonon-Electron interactionPhonon scattering of carriers 精品课件精品课件！精品课件精品课件！Conservation of energy and momentum Photonlarge energy, very litter momentum Room