Booth J M, Drumm D W, Casey P S, Smith J S, Russo S P
Theoretical Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, Australia.
CSIRO Manufacturing, Clayton, VIC, Australia.
J Chem Phys. 2016 Jun 28;144(24):244110. doi: 10.1063/1.4954508.
It is demonstrated that the signatures of the Hubbard Model in the strongly interacting regime can be simulated by modifying the screening in the limit of zero wavevector in Projector-Augmented Wave GW calculations for systems without significant nesting. This modification, when applied to the Mott insulator CuO, results in the opening of the Mott gap by the splitting of states at the Fermi level into upper and lower Hubbard bands, and exhibits a giant transfer of spectral weight upon electron doping. The method is also employed to clearly illustrate that the M1 and M2 forms of vanadium dioxide are fundamentally different types of insulator. Standard GW calculations are sufficient to open a gap in M1 VO2, which arise from the Peierls pairing filling the valence band, creating homopolar bonds. The valence band wavefunctions are stabilized with respect to the conduction band, reducing polarizability and pushing the conduction band eigenvalues to higher energy. The M2 structure, however, opens a gap from strong on-site interactions; it is a Mott insulator.
结果表明，对于没有明显嵌套的系统，在投影增强波GW计算中，通过在零波矢极限下修改屏蔽效应，可以模拟强相互作用 regime 下哈伯德模型的特征。这种修改应用于莫特绝缘体CuO时，会导致费米能级处的态分裂为上、下哈伯德带，从而打开莫特能隙，并在电子掺杂时表现出光谱权重的巨大转移。该方法还被用于清楚地说明二氧化钒的M1和M2形式是根本不同类型的绝缘体。标准GW计算足以在M1 VO2中打开一个能隙，这是由佩尔斯配对填充价带产生同极键引起的。价带波函数相对于导带稳定，降低了极化率，并将导带本征值推至更高能量。然而，M2结构由于强在位相互作用而打开一个能隙；它是一种莫特绝缘体。
