共查询到20条相似文献,搜索用时 125 毫秒
1.
采用线性组合算符与变分相结合的方法讨论了无限深量子阱中强耦合束缚极化子的温度效应.给出了无限深量子阱中束缚极化子的基态能量和振动频率随温度和阱宽的变化关系.对RbCl晶体进行了数值计算,结果表明:当温度升高时,量子阱中强耦合束缚极化子的振动频率增大,基态能量的绝对值增大;并且基态能量的绝对值随阱宽增大而增大. 相似文献
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李亚利 《原子与分子物理学报》2012,29(4):666-670
采用线性组合算符与变分相结合的方法讨论了无限深量子阱中强耦合束缚极化子的温度效应.给出了无限深量子阱中束缚极化子的基态能量和振动频率随温度和阱宽的变化关系.对RbCl晶体进行了数值计算,结果表明:当温度升高时,量子阱中强耦合束缚极化子的振动频率增大,基态能量的绝对值增大;并且基态能量的绝对值随阱宽增大而增大. 相似文献
3.
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
4.
研究多原子半无限晶体中电子与表面光学(SO)声子耦合强,而与体纵光学(LO)声子耦合弱的极化子的激发态性质.采用线性组合算符和幺正变换方法导出与SO声子耦合强而与LO声子耦合弱情形下极化子的基态能量、第一内部激发态能量和激发能量.结果表明,多原子半无限晶体中与SO声子耦合强,而与LO声子耦合弱的极化子的基态能量、第一内部激发态能量不仅包含不同支LO声子和不同支SO声子与电子耦合的能量,而且也包含不同支SO声子之间相互作用贡献的附加能量.激发能量与体纵光学声子无关. 相似文献
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采用Huybrechts线性组合算符和Lee-Low-Pines变换法研究了温度和极化子效应对量子阱中激子与界面光学声子强耦合又与体纵光学声子弱耦合体系基态的影响,推导出激子基态的诱生势和基态能量的移动的表达式. 以AgCl/AgBr量子阱为例进行了数值计算,结果表明,由激子-界面光学声子强耦合所产生的激子基态的诱生势和基态能量的移动随温度的升高而增大,而由激子-体纵光学声子弱耦合所产生的激子基态的诱生势和基态能量的移动随温度的升高而减小.
关键词:
量子阱
强耦合激子
极化子效应
温度依赖性 相似文献
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根据Pekar类型变分法在电子与声子强耦合的条件下计算了抛物量子点中强耦合极化子的基态能量.讨论了电子-声子耦合强度,量子点受限长度对基态能量的影响,同时引进温度参数并讨论了其对基态能量的影响,结果得出在低温的条件下,耦合强度和受限长度对基态的能量影响起主要作用;在高温的条件下,温度对基态的能量影响起主要作用,而耦合强度与受限长度的影响很小. 相似文献
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Electronic Structure of the Positive Radical of 13C-Labeled Poly(3-Octylthienylene Vinylene) Polymer
Yun Ling Hanne Diliën Dirk Vanderzande Peter J. Adriaensens Sabine Van Doorslaer 《Applied magnetic resonance》2014,45(9):827-839
Poly(3-octylthienylene vinylene) (O-PTV) has a great potential as low-bandgap p-type semiconductor for photovoltaic applications. Here, the positive radical state (positive polaron) is induced chemically in the O-PTV polymer in which the vinylene sites are selectively 13C-labeled. Using multi-frequency continuous wave and pulsed electron paramagnetic resonance, the g tensor and maximum 1H and 13C hyperfine couplings are determined. A comparative density functional theory (DFT) analysis of PTV-like oligomers is performed. The experimental parameters suggest a larger localization of the positive polaron than follows from the DFT analysis. The counter anion may play a crucial role in localizing the polaron. 相似文献
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Polaron effects in cylindrical GaAs/AlxGa1−xAs core–shell nanowires are studied by applying the fractal dimension method. In this paper, the polaron properties of GaAs/AlxGa1-xAs core–shell nanowires with different core radii and aluminum concentrations are discussed. The polaron binding energy, polaron mass shift, and fractal dimension parameter are numerically determined as functions of shell width. The calculation results reveal that the binding energy and mass shift of the polaron first increase and then decrease as the shell width increases. A maximum value appears at a certain shell width for different aluminum concentrations and a given core radius. By using the fractal dimension method, polaron problems in cylindrical GaAs/AlxGa1-xAs core–shell nanowires are solved in a simple manner that avoids complex and lengthy calculations. 相似文献
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多原子极性晶体中表面激子的性质 总被引:1,自引:1,他引:0
本文研究多原子极性晶体中表面激子的性质.采用微扰法导出表面激子的有效哈密顿量.多支LO声子对表面激子的自陷能和有效势的影响是相互独立的.对于Wannier激子,电子、空穴间的相互作用的有效势仍是库仑型的,只是介电常数约化为 .多支LO声子的作用使激子的自陷能更低.并得到激子的自陷条件. 相似文献
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有不少的极性半导休,电子与表面声学声子和体纵光学声子的耦合弱,但与表面光学声手的耦台强.本文同时考虑体纵光学声子、表面光学声子以及表面声学声予的影响,研究这类半导体的表面电予的性质,采用线性组合算符和拉格朗日乘子法,导出其有效哈密顿量和重正化质量。 相似文献
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A. É. Myasnikova É. N. Myasnikov 《Journal of Experimental and Theoretical Physics》1999,88(1):101-104
Owing to a funadmentally erroneous approach to calculations of the effective polaron mass (calculations that use a model without
spatial dispersion of the lattice polarizability), the polaron inertial mass has never before been distinguished from the
mass as a measure of kinetic energy. In this paper we derive an expression for the tensor of the inertial mass of a large
polaron. The tensor is found to be fully determined by two components: the longitudinal component, corresponding to the case
where the force acting on the polaron is parallel to the polaron velocity, and the transverse component, corresponding to
the case where the acceleration is perpendicular to the polaron velocity. The components of the polaron inertial mass tensor
depend quasirelativistically on the polaron velocity due to the quasirelativistic compression of the polarization field in
the direction of motion, which constitutes the effect of spatial dispersion of the lattice polarizability. We derive a formula
that approximates the dependence of the components of the polaron mass tensor on all the parameters: the frequency and dispersion
of the phonons, the polaron velocity, and the effective dielectric constant.
Zh. éksp. Teor. Fiz. 115, 180–186 (January 1999) 相似文献
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E. V. Korovkin 《Physics of the Solid State》2017,59(3):490-494
The assumption has been made that defects binding free polarons in colored alkali halide crystals are F'-center, i.e., defects that slow down the motion of dislocations (photoplastic effect). This assumption has been confirmed by the experiments performed in this study. Thus, the anion vacancy in alkali halide crystals at a low temperature can capture three electrons: two electrons at a deep level (F'-center) and one electron in a bound polaron state. This electron is retained due to the energy gain in the interaction of a local deformation of the polaron and a local deformation surrounding the F'-center, despite the presence of the Coulomb repulsion. 相似文献
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A. É. Myasnikova É. N. Myasnikov 《Journal of Experimental and Theoretical Physics》1997,85(1):152-155
We show that, beginning with the works of L. D. Landau and S. I. Pekar, the effective mass of a large polaron has been determined
with a crucial error. Since all such research ignored the spatial dispersion of the lattice polarizability, the maximum group
velocity of phonons is found to be zero, so that the phonon “cloud” of a polaron is unable to follow the polaron. We allow
for the spatial dispersion of the lattice polarizability and derive an expression for the effective polaron mass valid over
the entire velocity range in which a polaron can exist: from zero to the maximum group velocity of phonons. According to this
expression, the polaron mass depends not only on the phonon frequency, reciprocal effective dielectric constant, and the carrier
mass but also on the maximum group velocity of phonons interacting with the carrier and on the polaron velocity.
Zh. éksp. Teor. Fiz. 112, 278–283 (July 1997) 相似文献
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I. A. Merkulov K. V. Kavokin G. Mackh B. Kuhn-Heinrich W. Ossau A. Waag G. Landwehr D. R. Yakovlev 《Physics of the Solid State》1997,39(11):1859-1863
An experimental and theoretical study of the magnetic polaron states of two-dimensional excitons in quantum wells based on
semimagnetic semiconductors (Cd,Mn)Te is reported. It is shown that magnetic-polaron formation in in-plane magnetic fields
leads to a lowering of the system symmetry, provided the fields are not too strong. The magnetic moment of the polaron thus
formed is not parallel to the external magnetic field and contains a component normal to the quantum-well plane. This spontaneous
lowering of the symmetry results in a change of the polarization characteristics of the luminescence from magnetic polaron
states and in a weakening (compared to the three-dimensional case) in the efficiency of magnetic field-induced polaron suppression.
Fiz. Tverd. Tela (St. Petersburg) 39, 2079–2084 (November 1997) 相似文献