Fano effects

K. Kobayashi, H. Aikawa, S. Katsumoto, Y. Iye, Tuning of the Fano effect through a quantum dot in an Aharonov-Bohm interferometer, Phys. Rev. Lett. 88 (2002) 256806/1. 

U. Fano, Effects of configuration interaction on intensities and phase shifts, Phys. Rev. 124 (1961) 1866. 

Free carriers change Raman spectra, either by single particle contribution to the spectrum, or by phonon- plasmon interaction. In addition, interference of electronic transition continua with single phonon excitations may lead to Fano line shapes, as mentioned in the introduction. The Fano effect is encountered in p-doped Si crystals, as shown in Fig. 4.8-19. The shown lines correspond to the respective Raman active mode at 520 cm for crystals with 4 different carrier concentrations, excited with a red laser. The continuous line is calculated according to Eq. 4.8-6. Antiresonance on the low frequency side and line enhancement on the high frequency side are a consequence of the positive value of Q. A reverse type of behavior is possible in the case of a negative Q. 

In the case of p-type doping in Si, the Fano effect is evident in the asymmetric broadening of the optical phonon line to higher frequency. There is indeed... 

Strain, and confinement (or crystal quality) effects. Secondly, the n-type Fano effect is much weaker, usually not emerging in measured Raman spectra until doping levels exceed 10 ° cm [44],... 

Another consequence of spin-orbit coupling is the occurrence of the Fano effect in photoemission (Fano 1969a,b). This term denotes the phenomenon where we obtain a spin-polarized photoelectron current even for a paramagnetic solid if circularly polarized light is used for excitation (Heinzmann et al. 1972). Due to time-reversal... 

Using the full-potential geometry influences to some extent the peak positions and also the relative peak heights. Both modifications bring the theoretical spectrum in closer agreement with experiment. The same experiment has also been carried out for other systems, for example, GaAs (Fluchtmann et al. 1999), which is the standard source for spin-polarized electron beams by making use of the Fano effect (Meier 1985). 

This phenomenon, first pointed out by Fano [143] and called the Fano effect, has been used to produce spin-polarised electron sources [144]. Sources based on irradiating atoms are now mainly of academic importance, because solid state sources based on GaAs devices yield a higher current more simply. 

About SEFS as a spectroscopic feature, it can be said that this structure is a manifestation of effects of the strong electron-hole correlation (with a hole on the atom core level) upon excitation of the atom by an electron impact. As opposed to the classical autoionization effects (Fano effects), where the presence of a resonance level is assumed, in the present case a strongly correlated state is observed... 

U. Fano. Effects of Configuration Interaction on Intensities and Phase Shifts. Physical Revew 1961 Dec 15 124(6) 1866-1878. 

Effect of the boron doviner level. The evolution of the Fano effect with the boron doping level increase is a very important observation. The diamond line at 1332 cm i decreases in intensity... 

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