Donor impurity-related linear and nonlinear intraband optical absorption coefficients in quantum ring: Effects of applied electric field and hydrostatic pressure

Nanoscale Research Letters (Impact Factor: 2.78). 09/2012; 7(1):538. DOI: 10.1186/1556-276X-7-538
Source: PubMed


The linear and nonlinear intraband optical absorption coefficients in $GaAs$ three-dimensional single quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and electric field, applied along the growth direction of the heterostructure, the energies of the ground (1s) and first excited (2s) sates of a donor impurity have been found using the effective mass approximation and a variational method. The energies of these states are examined as functions of the structure (inner and outer radii as well as the height of ring), electric field and hydrostatic pressure. We have also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as a function of incident photon energy for different geometric configurations, hydrostatic pressure, and external electric field. It is found that the variation of distinct sizes of the structure leads to either a redshift and/or a blueshift of the resonant peaks of the intraband optical spectrum. In addition we have found that the application of an electric field leads to a redshift whereas the influence of hydrostatic pressure leads to a blueshift (in the case of on-ring-center donor impurity position) of the resonant peaks of the intraband optical spectrum.

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Available from: M. E. Mora-Ramos
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    • "Los resultados más importantes pueden ser resumidos así: (1) los niveles excitónicos no aparecen equidistantes y se desdoblan con el campo magnético, reflejando con ello las características asociadas a la geometría de los anillos, (2) las oscilaciones de Aharonov–Bohm de excitones, que son características de anillos unidimensionales no aparecen en sistemas de dimensiones finitas, y (3) los campos eléctricos generan nuevas reglas de selección para las transiciones inter e intrabanda. Estudios recientes han reportado el coeficiente de absorción óptica intrabanda lineal y no lineal en anillos cuánticos de GaAs aislados bajo los efectos de presión hidrostática y campo eléctrico (Barseghyan, et al., 2012). Entre los resultados arrojados en dicha investigación está que la variación de los diferentes tamaños característicos de la geometría de la estructura puede generar corrimientos bien sea al rojo o al azul de los picos resonantes del espectro óptico intrabanda. "

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