Electronic states in GaAs-(Al,Ga)As eccentric quantum rings under nonresonant intense laser and magnetic fields

WOS: 000457753000024

PubMed ID: 30723242

The features of the electron energy spectrum in eccentric two-dimensional GaAs-AlGaAs quantum rings of circular shape are theoretically investigated taking into account the effect of externally applied magnetic and intense laser fields. Analytical expressions for the laser-dressed confining potential in this kind of quantum ring geometry are reported for the first time. Finite element method is used to solve the resulting single-particle effective mass two-dimensional partial differential equation. It is shown that the allowed level spectrum is greatly influence by the external probe as well as by the breaking of geometric symmetry related to the changes in eccentricity. In presence of an intense laser field, the conduction band confining profile suffers strong modifications along the structure, with an additional contribution to symmetry breaking. These modifications of electronic quantum states reflect in the intraband optical absorption. Accordingly, the features of the intraband transitions are discussed in detail, revealing the significant influence of the magnetic field strength and laser field intensity and polarization, together with eccentricity, in the allowing of ground-to-excited states transitions and their corresponding intensities.

Universidad EIA; CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); CODI-Universidad de Antioquia (project "Efectos de capas delta dopadas en pozos cuanticos como fotodetectores en el infrarrojo"); CODI-Universidad de Antioquia (project "Efectos opticos intersubbanda, no lineales de segundo orden y dispersion Raman, en sistemas asimetricos de pozos cuanticos acoplados"); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2018-2019); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (ALM-exclusive dedication project 2018-2019); Colombian Agency El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologa y la Innovacion, Francisco Jose de Caldas-COLCIENCIAS; Mexican Conacyt [206772]; Universidad de Antioquia

J.A. Vinasco acknowledges the support and fruitful cooperation with Prof. Dr. A. Radu during his doctoral stay at the Department of Physics, "Politehnica" University of Bucharest, where part of this work was done. This research was partially supported by Colombian Agencies: Universidad EIA, CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia and projects "Efectos de capas delta dopadas en pozos cuanticos como fotodetectores en el infrarrojo" and "Efectos opticos intersubbanda, no lineales de segundo orden y dispersion Raman, en sistemas asimetricos de pozos cuanticos acoplados"), and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2018-2019 and ALM-exclusive dedication project 2018-2019). This work used resources of the Centro Nacional de Processamento de Alto Desempenho em Sao Paulo (CENAPAD-SP). J.A. Vinasco acknowledges the doctoral financial support from the Colombian Agency El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologa y la Innovacion, Francisco Jose de Caldas-COLCIENCIAS. M.E. Mora-Ramos acknowledges support from Mexican Conacyt through Grant 206772. The authors are grateful to the Universidad EIA and Universidad de Antioquia for financial support through the EIA-UdeA-UdeM-project "Generacion de segundo armonico, rectificacion optica y dispersion Raman entre estados electronicos en pozos cuanticos acoplados".