Advanced Solid State Physics

Figure 107: Plot of the dielectric function over the photon energy. At every maximum the valence and the conduction bands are pa ...

13.2 Collisionless Metal In collisionless metals electrons travel ballistically which means that the scattering time and the mea ...

with eqn. (219): ⇒χ(ω) = σ(ω) iω 0 = ne^2 iω 0 m (πδ(ω) + i ω ) (226) We used: x(ω,t) = x(ω)e−iωt⇒v(ω,t) = x(ω)e−iωt(−iω)⇒x(ω) ...

13.3 Diffusive Metals In diffusive metals, there is one component which is out of phase and one component which is in phase (eqn ...

Fig. 109 shows the real part of the dielectric function: ′(ω) = 1− ω^2 p ω^2 +τ^12 (235) For diffusive metals the real part of ...

The second type is called Palik, which is an optical measurement method. The third plot is calculated via density functional the ...

Figure 111: Real part of a dielectric function of a semiconductor. The imaginary part would have a peak around the residents. Fi ...

14 Dielectrics and Ferroelectrics 14.1 Excitons 14.1.1 Introduction An exciton is a bound state of an electron and a hole in a s ...

Figure 114: Dispersion relationship for a semiconductor with the energy levels of excitons The concentration of the created exci ...

Figure 115: Absorption experiment to show the excitation levels of excitons Figure 116: Result of an experiment to show the exis ...

Figure 117: Phase diagram for photoexcited electrons and holes in unstressed silicon In fig. 118 we see the energy dependence of ...

Figure 118: Solution of the energy, when frenkel excitons move through a perfect crystal is important that there are well define ...

Figure 119: Principle of optical measurement Figure 120: Principle of reflection electron energy loss spectroscopy troscopy). If ...

Figure 121: The principle of XPS and UPS Figure 122: Photoemission spectroscopy for silver ...

Figure 123: Stokes and anti-stokes process of Raman spectroscopy The equations for the conservation of energy and momentum are: ...

with the additional term of the phonon wave. Some of the scattered phonons are forbidden by crystal symmetry and in this case, t ...

14.3 Dielectrics 14.3.1 Introduction Dielectrics seem to be really boring materials for electronics, because an ideal dielectric ...

Figure 126: Different loss tangents for different materials. Remember that they are small numbers and because of thattan(δ)∼δ ...

Figure 127: Dependence of the dielectric constant of the temperature and the voltage 14.3.2 Polarizability There are different s ...

compared to the wavelength of light. It has to be said, that every material has a polarization, because everything consists of a ...