HOLSTEIN MODEL IN INFINITE DIMENSIONS
HOLSTEIN MODEL IN INFINITE DIMENSIONS
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DOI：
10.1103/physrevb.48.6302
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发表时间：
1993-09-01
影响因子：
3.7
通讯作者：
SCALAPINO, DJ
中科院分区：
文献类型：
--
作者：
FREERICKS, JK;JARRELL, M;SCALAPINO, DJ
蒙特卡罗模拟进行了检查超导性和电荷密度波波动在无限维电子-声子霍尔斯坦模型。电子-声子系统在具有吸引力的静态Falicov-Kimball模型和具有吸引力的瞬时Hubbard模型之间进行插值，前者总是表现出电荷密度-波序，后者总是作为声子频率的函数进行超导。半填充时的最大电荷密度波转变温度比有效电子带宽小一个数量级，并且几乎与声子频率无关。最高超导转变温度与声子频率密切相关，并以最高电荷密度波转变温度为界。将精确解与弱耦合展开和强耦合展开进行了比较。随着电子-声子相互作用的增加，有效声子势变为非谐波并发展为双阱结构，双阱结构加深。
Monte Carlo simulations are performed to examine superconductivity and charge-density-wave fluctuations in the infinite-dimensional electron-phonon Holstein model. The electron-phonon system interpolates between an attractive, static, Falicov-Kimball model that always exhibits charge-density-wave order and an attractive, instantaneous, Hubbard model that always superconducts as a function of phonon frequency. The maximum charge-density-wave transition temperature at half-filling is an order of magnitude smaller than the effective electronic bandwidth and is virtually independent of the phonon frequency. The maximum superconducting transition temperature depends strongly on phonon frequency and is bounded from above by the maximum charge-density-wave transition temperature. The exact solution is compared to both weak-coupling expansions and strong-coupling expansions. The effective phonon potential becomes anharmonic and develops a double-well structure that deepens as the electron-phonon interaction increases.