Electron–phonon interaction for adiabatic anharmonic phonons
Electron–phonon interaction for adiabatic anharmonic phonons
复制标题
绝热非简谐声子的电子-声子相互作用
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
D. Schneider
中科院分区：
文献类型：
--
作者：
K. Ziegler;D. Schneider
研究了在绝热声子极限下的类荷尔斯坦电子-声子耦合模型。声子分布是非调和的，有两个简并极大值。该模型可以与相关二元合金中的费米子相关联，并描述微观相分离。我们讨论了弱和强电子-声子耦合极限，并给出了定性相图。就声子位移而言，它由均匀相、交替相和无序相组成。均匀相和交替相之间存在一级相变，交替相和无序相之间存在二级相变。用动力学平均场理论分析了无序相中间隙的打开。
A model with Holstein-like electron–phonon coupling is studied in the limit of adiabatic phonons. The phonon distribution is anharmonic with two degenerate maxima. This model can be related to fermions in a correlated binary alloy and describes microscopic phase separation. We discuss the weak and strong electron–phonon coupling limits and present a qualitative phase diagram. In terms of the phononic displacements it consists of a homogeneous, an alternating, and a disordered phase. There is a first-order phase transition between the homogeneous and the alternating phases, and a second-order phase transition between the alternating and the disordered phases. The opening of a gap inside the disordered phase is treated using dynamical mean-field theory.