Effect of dispersion of “vertically” polarized collective plasmon-LO-phonon excitations on Raman scattering of strongly coupled GaAs/AlAs superlattices

Pusep, Yu. A.; Silva, M. T. O.; Moshegov, N. T.; Galzerani, J. C.

doi:10.1103/physrevb.61.4441

Cited by 10 publications

(16 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the recent articles [4] we have demonstrated that in the intentionally disordered GaAs/AlGaAs SLs the observed asymmetry of the Raman lines associated to the plasmon-like collective excitations is due to the effect of their localization. In this case the magnitude of the localization length of the relevant collective excitations indicates the strength of the correlation effects (the longer localization length, the stronger electron correlation) and it can be determined using the for-mula [4]:…”

mentioning

confidence: 95%

“…[3], the phasebreaking length determines the minimum width of an electron wave packet and therefore, it may serve as the lower cutoff for the localization length. On the other hand, the localization length associated with the indetermination of the quasimomentum of plasmons can be measured by Raman scattering [4].In strongly disordered bulk materials the Landau damping determines the localization length of plasmons [5]. Whereas, the quantization of the electron energy in superlattices sets new limits.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…In this case the magnitude of the localization length of the relevant collective excitations indicates the strength of the correlation effects (the longer localization length, the stronger electron correlation) and it can be determined using the for-mula [4]:…”

mentioning

confidence: 99%

“…The dispersions of the collective modes were calculated in the direction of propagation of the light using the random phase approximation (RPA) as in Ref. [4].…”

mentioning

confidence: 99%

See 4 more Smart Citations

Coherence of elementary excitations in disordered GaAs/AlGaAs superlattices

Pusep¹

2006

Braz. J. Phys.

Self Cite

View full text Add to dashboard Cite

The localization properties of the single-particle and collective electron excitations were investigated in the intentionally disordered GaAs/AlGaAs superlattices by weak field magnetoresistance and Raman scattering. The localization length of the individual electron was found to be considerably larger than that one of the collective excitations. This suggests that the disorder has weaker effect on the electrons than on their collective motion and that the interaction which gives rise to the collective effects increases localization.Keywords: Coherence; Localization; SuperlatticesThe localization of elementary excitations rather relates to the wave nature of their wave functions than to the distribution of the electron charge density in the real space. Consequently, the insulating state, which results in a zero dc conductivity, is determined by the localization of the ground electron wave function. Therefore, a direct probe of the properties of the wave functions is a central subject of the localization problem. Any elementary excitations having a wave origin reveal the same qualitative aspects of localization. However, their specific features may result in different characteristic performances. A generality of the localization in the cases of the individual electrons and their collective motions (plasmons) was firstly pointed out in Ref. [1], where the random semiconductor superlattices (SLs) were also proposed as a tool to control the strength of the disorder. The essential difference between electrons and plasmons is in the dynamic polarization which determines the collective electron motion. Hence, the interaction between electrons intrinsically determines features of their collective excitations (plasmons). Therefore, the comparison between the localization properties of the plasmons and the electrons may shed some light on the problem of how the interaction influences localization.In this way the phase-breaking length of the individual electrons can be obtained by the weak-field magnetoresistance measurements [2]. As it was stated in Ref. [3], the phasebreaking length determines the minimum width of an electron wave packet and therefore, it may serve as the lower cutoff for the localization length. On the other hand, the localization length associated with the indetermination of the quasimomentum of plasmons can be measured by Raman scattering [4].In strongly disordered bulk materials the Landau damping determines the localization length of plasmons [5]. Whereas, the quantization of the electron energy in superlattices sets new limits. Namely, the disorder determines the localization of plasmons when their energy is placed in the range of the minigap of the single-particle spectrum. Therefore, a direct comparison between the disorder induced localization properties of the single-particle and the collective electron excitations is possible for those of them propagated along the quantization direction (perpendicular to the layers).In this work we used the intentionally disordered GaAs/AlGaAs SLs where the ve...

show abstract

mentioning

confidence: 95%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…The dispersions of the collective modes were calculated in the direction of propagation of the light using the random phase approximation (RPA) as in Ref. [4].…”

mentioning

confidence: 99%

See 3 more Smart Citations