Feynman variational path integral theory was used to obtain the ground state energy of a polaron in a quantum well in the presence of a Coulomb potential for arbitrary values of the electron phonon coupling constan...Feynman variational path integral theory was used to obtain the ground state energy of a polaron in a quantum well in the presence of a Coulomb potential for arbitrary values of the electron phonon coupling constant α . Numerical and analytical results showed that the energy shift was more sensitive to α than to the Coulomb binding parameter ( β ) and increased with the decrease of effective quantum well width l Z . It was interesting that due to the electronic confinement in the quasi 2D (quantum well) structures, the lower bound of the strong coupling regime was shifted to smaller values of α . Comparison of the polaron in the quantum well with that in the quantum wire or dot showed that the polaronic effect strengthened with decrease of the confinement dimension.展开更多
By exact resolution of coupled ideal chains connecting an extra side site,we show that the so-called'anti-resonant effect' is suppressed when the electron energy is inside the overlap region of extended bands ...By exact resolution of coupled ideal chains connecting an extra side site,we show that the so-called'anti-resonant effect' is suppressed when the electron energy is inside the overlap region of extended bands of the idealtight-binding chains.When the electronic energy is outside the band overlap region,the existence of 'anti-resonanteffect' is tuned by details of local connectivity around the extra side site and can be suppressed by introduction ofmagnetic flux.展开更多
基金Supported by National Science Fundation of China(60878002)the Science and Technology Committee of Guangdong Province(2010A080802002,2010B080704002,2010B010800031,2010B090400130 and 8251009101000002)the Science and Technology Bureau of Guangzhou(2009J1-C421-1)
文摘Feynman variational path integral theory was used to obtain the ground state energy of a polaron in a quantum well in the presence of a Coulomb potential for arbitrary values of the electron phonon coupling constant α . Numerical and analytical results showed that the energy shift was more sensitive to α than to the Coulomb binding parameter ( β ) and increased with the decrease of effective quantum well width l Z . It was interesting that due to the electronic confinement in the quasi 2D (quantum well) structures, the lower bound of the strong coupling regime was shifted to smaller values of α . Comparison of the polaron in the quantum well with that in the quantum wire or dot showed that the polaronic effect strengthened with decrease of the confinement dimension.
基金Supported by the National Natural Science Foundation of China under Grant No.10604006Super Computer Center of Beijing Normal University
文摘By exact resolution of coupled ideal chains connecting an extra side site,we show that the so-called'anti-resonant effect' is suppressed when the electron energy is inside the overlap region of extended bands of the idealtight-binding chains.When the electronic energy is outside the band overlap region,the existence of 'anti-resonanteffect' is tuned by details of local connectivity around the extra side site and can be suppressed by introduction ofmagnetic flux.
