Theoretical Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India.
J Phys Condens Matter. 2011 Jan 19;23(2):025601. doi: 10.1088/0953-8984/23/2/025601. Epub 2010 Dec 16.
We present the effect of next-nearest-neighbor hopping on Holstein polarons. The energy and wavefunction of the ground state and first excited state are obtained by using a conjugate-gradient technique on the variational Hilbert space of the electron-phonon (e-ph) system. We increase the size of the variational space systematically to obtain high accuracy. With the converged wavefunction at our disposal we obtain various physical quantities and correlation functions to get a holistic insight into the physics of e-ph interaction. Our study reveals that the effect of next-nearest-neighbor hopping is most prominent at the physically interesting crossover regime of the e-ph coupling and in the adiabatic regime. We have also performed analytical strong coupling second order perturbation with a Lang-Firsov (LF) phonon basis to account for some features in the strong coupling regime.
我们研究了最近邻跳跃对极化子的影响。利用电子-声子（e-ph）系统变分希尔伯特空间中的共轭梯度技术，我们得到了基态和第一激发态的能量和波函数。我们系统地增加变分空间的大小以获得高精度。利用我们掌握的收敛波函数，我们获得了各种物理量和相关函数，以全面了解 e-ph 相互作用的物理性质。我们的研究表明，最近邻跳跃的影响在 e-ph 耦合的物理有趣交叉区域和绝热区域最为显著。我们还使用基于 Lang-Firsov（LF）声子的解析强耦合二阶微扰理论来解释强耦合区域的一些特征。
