共查询到20条相似文献,搜索用时 31 毫秒
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采用求解能量本征方程、幺正变换和变分相结合的方法,研究声子和磁场对量子环中极化子性质的影响. 对KBr量子环的数值计算表明,电子或极化子的基态能量随量子环频率(或平均半径)的增大而增大,极化子基态能移随量子环频率的增大(或平均半径的减小)而减小,极化子中的平均声子数随量子环频率的增大(或平均半径的减小)而增大. 当有垂直磁场时,极化子基态能量和基态能移与外磁场及电子转动状态有关. 随着磁场强度的增大,基态能量出现简并且呈现非周期性振荡;能移随磁场强度的增大(或转动量子数绝对值的减小)而减小. 相似文献
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LIU Jia XIAO Jing-Lin HUO Shu-Fen CHEN Zi-Yui 《理论物理通讯》2007,48(5):930-934
We investigate the influence of a perpendicular magnetic field on a bound polaron near the interface of a polar-polar semiconductor with Rashba effect. The external magnetic field strongly changes the ground state binding energy of the polaron and the Rashba spin-orbit (SO) interaction originating from the inversion asymmetry in the heterostructure splits the ground state binding energy of the bound polaron. In this paper, we have shown how the ground state binding energy will be with the change of the external magnetic field, the location of a single impurity, the wave vector of the electron and the electron areal density, taking into account the SO coupling. Due to the presence of the phonons, whose energy gives negative contribution to the polaron's, the spin-splitting states of the bound polaron are more stable, and we find that in the condition of week magnetic field, the Zeeaman effect can be neglected. 相似文献
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The energy levels of a polaron in a wurtzite nitride finite parabolic quantum well (PQW)are studied by a modified Lee-Low-Pines variational method. The ground state of the polaron, the transition energy from first exited state to the ground state and the
关键词:
氮化物抛物量子阱
电子-声子相互作用
极化子 相似文献
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磁场中强耦合表面极化子的性质 总被引:10,自引:5,他引:5
本文研究磁场中强耦合表面极化子的性质,采用线性组合算符法导出表面极化子的基态能量和振动频率.对AgCl和KCl晶体进行了数值计算.结果表明,磁场中强耦合表面极化子的振动频率随磁场的增加而增大,基态能量随磁场的增加而减少. 相似文献
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We investigate the electric field effect on the ground state (GS), the first-excited state (FES) and the excitation energies of a strong-coupled polaron in an asymmetric Gaussian potential (AGP) quantum well (QW) by using a variational method of the Pekar type (VMPT). By employing the quantum statistics theory (QST), we also study the temperature effects on the state energies (SE). It is found that the SE of polaron are an increasing function of temperature. The polaron's SE are decreasing functions of electric field, but the excitation energy is an increasing one. 相似文献
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研究了磁场作用下石墨烯中电子与表面光学声子弱耦合情况下的极化子的性质。采用线性组合算符和Pekar变分法分别推导出了石墨烯中弱耦合极化子的基态能量E0、第一激发态能量E1和跃迁频率ω随磁场强度B和德拜截止波数kd之间的变化关系。数值计算结果表明,极化子的基态能量E0随磁场强度B变化的曲线(kd一定时)和E0随kd的变化曲线(B一定时)均会分裂成对称的两条,并且当B一定时E0的绝对值随kd的增加而增加。在kd一定时,极化子的第一激发态能量E1和跃迁频率ω均为磁场B的增函数;在B一定时,E1和ω均随kd的增加而增大。 相似文献
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《理论物理通讯》2017,(3)
Employing variational method of Pekar type(VMPT), this paper investigates the first-excited state energy(FESE), excitation energy and transition frequency of the strongly-coupled polaron in the Cs I quantum pseudodot(QPD)with electric field. The temperature effects on the strong-coupling polaron in electric field are calculated by using the quantum statistical theory(QST). The results from the present investigation show that the FESE, excitation energy and transition frequency increase(decrease) firstly and then at lower(higher) temperature regions. They are decreasing functions of the electric field strength. 相似文献
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A variational approach is used to study the ground state of a bound polaron in a spherical quantum dot under an external electric field. The binding energy of the hydrogenic impurity state is calculated by taking the interaction of an electron with both the confined longitudinal optical phonons and the surface optical phonons into account. The interaction between impurity and longitudinal optical phonons has also been considered to obtain the binding energy of a bound polaron. It shows that the polaron effects give significant corrections to the binding energy and its Stark energy shift. The external electric field increases the phonon contributions to the binding energy. 相似文献
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《Superlattices and Microstructures》1994,16(1):83-86
It is shown that the hole state centred in the middle of the well can become unstable during magnetic polaron formation resulting in a polaron state connected with an interface. The criterion of formation of interface-trapped polarons in a quantum well with semimagnetic barriers is found. We have shown that in the case of the experimentally observed two-dimensional exciton magnetic polaron, interface trapping is prevented mainly due to the electron-hole Coulomb attraction. The effect of an external magnetic field on the stability criterion is also considered. 相似文献
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A variational scheme of the Pekar type is employed to study the strong-coupling optical polaron on the outer surface of the polar crystal under the influence of a magnetic field. The ground state energy and the effective mass of the polaron are obtained as functions of the magnetic field strength and the electron-surface optical phonon coupling constant. It is shown that the effective mass of the surface polaron appears in nonisotropic nature due to the coupling between the electron and the surface optical phonon. 相似文献
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《中国物理 B》2021,30(10):106702-106702
We investigate the polaron and molecular states of a fermionic atom with one-dimensional spin–orbit coupling(SOC)coupled to a three-dimensional spinless Fermi sea. Because of the interplay among the SOC, Raman coupling and spinselected interatomic interactions, the polaron state induced by the spin–orbit coupled impurity exhibits quite unique features. We find that the energy dispersion of the polaron generally has a double-minimum structure, which results in a finite center-of-mass(c.m.) momentum in the ground state, different from the zero-momentum polarons where SOC are introduced into the majority atoms. By further tuning the parameters such as the atomic interaction strength, a discontinuous transition between the polarons with different c.m. momenta may occur, signaled by the singular behavior of the quasiparticle residue and effective mass of the polaron. Meanwhile, the molecular state as well as the polaron-to-molecule transition is also strongly affected by the Raman coupling and the effective Zeeman field, which are introduced by the lasers generating SOC on the impurity atom. We also discuss the effects of a more general spin-dependent interaction and mass ratio. These results would be beneficial for the study of impurity physics brought by SOC. 相似文献
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无限深量子阱中强耦合极化子的基态结合能 总被引:3,自引:0,他引:3
研究了无限深量子阱中极化子的基态性质,采用线性组合算符和变分相结合的方法导出了强耦合极化子的振动频率λ、基态能量E0和基态结合能Eb,讨论了阱宽L和电子-LO声子耦合强度α对强耦合极化子的振动频率λ、基态能量E0和基态结合能Eb的影响。通过数值计算,结果表明:强耦合极化子的振动频率和基态结合能随阱宽L的增大而减小,随电子-LO声子耦合强度α的增强而增大;基态能量随阱宽L的增大而减小,其绝对值随电子-LO声子耦合强度α的增强而增大;当量子阱阱宽L趋近于无限大和无限小两种极限情况下,分别与三维和二维极化子的结果相一致。 相似文献
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By a combination method of Lee–Low–Pines unitary transformation method and Pekar-type variational method, the ground state energy (GSE) of the bound polaron is studied in the asymmetrical Gaussian potential quantum well considering the temperature and electromagnetic field. The impacts of the temperature and asymmetrical Gaussian potential, electromagnetic field and phonon–electron coupling upon the GSE are obtained. The results show that the GSE of the bound polaron not only oscillates as the temperature changes regardless of the electromagnetic field and asymmetrical Gaussian potential and Coulomb impurity potential (CIP) and electron–phonon coupling but also has different rules with the electromagnetic field and asymmetrical Gaussian potential and CIP and electron–phonon coupling at different temperature zones. 相似文献
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弱耦合多原子半无限晶体中磁极化子的激发能量 总被引:1,自引:1,他引:0
近年来国内外对多原子极性晶体中磁极化子性质的研究十分活跃,Zorkani等采用变分法计算了束缚磁极化子的基态能量,Kandemir等采用束缚朗道态讨论了二维大磁极化子的基态和第一激发态能量,国内一些学者采用微扰法和新颖算符法讨论了多原子极性晶体中表面和体磁极化子的性质。采用线性组合算符和幺正变换,研究磁场中多原子半无限极性晶体中电子和光学声子弱耦合相互作用所产生的极化子的第一激发态能量及平均声子数。结果表明:当电子无限接近晶体表面时,磁极化子的基态能量仅为Landau能量;第一激发态能量为Landau基态能量的2倍;平均声子数等于各支与电子耦合的体光学声子数和表面光学声子数之和。而当电子处于晶体深处时,磁极化子的基态能量却为Landau基态能量与各支体光学声子以及表面光学声子分别耦合的能量之和;第一激发态能量仍为Landau基态能量的2倍;平均声子数等于各支与电子耦合的体光学声子数和与所处深度有关的各支体光学声子数之和,而与各支表面光学声子无关。 相似文献
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To understand the role of the magnetic polaron in magnetic and transport properties of Eu(1-x)LaxB6, we investigate the low carrier density ferromagnetic Kondo lattice model by using the Monte Carlo methods. We demonstrate that the magnetic-polaronic (MP) state with the insulating nature is realized in the phase-separated region in between the ferromagnetic and antiferromagnetic (AFM) states in the phase diagram. The insulating behaviors of EuB6 just above T(C) and of Eu(1-x)LaxB6 with 0.05相似文献