二维强耦合磁双极化子的自旋极化基态性质
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摘要
基于Lee-Low-Pines变分法研究了抛物量子点中二维强耦合磁双极化子的自旋极化基态性质,推导出磁双极化子的基态能量E0和声子平均数珡N随量子点受限强度ω0、介电常数比η、电子-声子耦合强度α和磁场的回旋频率ωc的变化规律。结果表明,磁双极化子的声子平均数珡N随α、ω0和ωc的增加而增大;磁双极化子的基态能量由两电子的单粒子能量Ee、两电子间库伦相互作用能Ec、电子自旋与磁场相互作用能ES、电子-声子相互作用能Ee-ph四部分组成;电子-声子相互作用能Ee-ph总是小于零,其绝对值随α、ω0和ωc的增加而增大,它是束缚态磁双极化子形成的有力因素;限定势和电子之间的库伦排斥能的存在不利于束缚态磁双极化子的形成;电子自旋-磁场相互作用的效应ES导致基态能级的"精细结构"。
The properties of the spin polarization ground state of the two-dimensional strong coupling magneto-bipolarons in a parabolic quantum dot are studied based on the Lee-Low-Pines variational method.The change law of the ground state energy E0 and the average number N of phonon of the magneto-bipolarons with the confinement strength ω0,the dielectric constant ratioη,the electron-phonon coupling strengthα,and the cyclotron frequencyωcare deduced.Numerical results indicate that the average number珡N of phonon will increase with increasing ω0,η,α,andωc.The ground state energy E0 consists of four parts:the single-article energy Eeof two electrons,the Coulomb interaction energy Ecbetween two electrons,the interaction energy ESbetween the electronic spin and the external magnetic field,and the interaction energy Ee-phof the electron with the LO phonons.Ee-phis always less than zero,and the absolute value|Ee-ph|will increase with increasing ω0,η,α,andωc.The electron-phonon interaction has the important influence on the formation of the magneto-bipolaron in the bound state;but the confinement potential and Coulomb repulsive potential between electrons are unfavorable to the formation of magneto-bipolarons in the bound state.The "fine structures" of the ground state energies are induced by the interaction energy between the electronic spin and the external magnetic field ES.
The properties of the spin polarization ground state of the two-dimensional strong coupling magneto-bipolarons in a parabolic quantum dot are studied based on the Lee-Low-Pines variational method.The change law of the ground state energy E0 and the average number N of phonon of the magneto-bipolarons with the confinement strength ω0,the dielectric constant ratioη,the electron-phonon coupling strengthα,and the cyclotron frequencyωcare deduced.Numerical results indicate that the average number珡N of phonon will increase with increasing ω0,η,α,andωc.The ground state energy E0 consists of four parts:the single-article energy Eeof two electrons,the Coulomb interaction energy Ecbetween two electrons,the interaction energy ESbetween the electronic spin and the external magnetic field,and the interaction energy Ee-phof the electron with the LO phonons.Ee-phis always less than zero,and the absolute value|Ee-ph|will increase with increasing ω0,η,α,andωc.The electron-phonon interaction has the important influence on the formation of the magneto-bipolaron in the bound state;but the confinement potential and Coulomb repulsive potential between electrons are unfavorable to the formation of magneto-bipolarons in the bound state.The "fine structures" of the ground state energies are induced by the interaction energy between the electronic spin and the external magnetic field ES.
引文
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[2]Dou X M,Sun B Q,Huang S S,et al.Single photon emission from a single InAs quantum dot[J].Chin Phys Lett,2008,25(2):501-504.
[3]Yan Z W.Self-trapping energy and effective mass of polaron in wurtzite nitride semiconductors[J].Mod Phys Lett B,2005,19(2):211-219.
[4]Huangfu Y F,Yan Z W.Bound polaron in a spherical quantum dot under an electric field[J].Physica E,2008,40(9):2982-2987.
[5]Chen S H,Yao Q Z.The effective mass of impuritybound polaron in a two-and three-dimensional quantum dot[J].J Low Temp Phys,2013,170(1-2):108-115.
[6]Eerdunchaolu,Xin W,Zhao Y W.Influence of lattice vibration on the ground-state of magnetopolaron in a parabolic quantum dot[J].Modern Physics Letters B,2010,24(27):2705-2712.
[7]Eerdunchaolu,Wuyunqimuge,Xiao X,et al.Effects of thermal lattice vibration on the effective potential of weak-coupling bipolaron in a quantum dot[J].Commun Theor Phys,2012,57(1):157-160.
[8]Eerdunchaolu,Wei Xin.Temperature dependence of the properties of strong-coupling bipolraon in a quantum dot[J].Physica B,2011,406:358-362.
[9]Xin W,Gao Z M,Wuyunqimuge,et al.Influence of temperature and LO phonon effects on the effective mass of quasi 0Dbipolarons in the strong-coupling limit[J].Superlattices and Microstructures,2012,52:872-879.
[10]LeeT D,Low F M,Pines D.The motion of slow electrons in a crystal[J].Phys Rev,1953,90:97-302.
[11]Chatterjee A.Strong-coupling theory f or the multidimensional free optical magnetopolaron[J].Phys Rev B,1990,41(9):1668-1670.