Interaction-range effects for fermions in one dimension
Interaction-range effects for fermions in one dimension
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DOI：
10.1103/physrevb.85.195115
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发表时间：
2012-01
影响因子：
3.7
通讯作者：
M. Hohenadler;S. Wessel;M. Daghofer;F. Assaad
中科院分区：
文献类型：
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作者：
M. Hohenadler;S. Wessel;M. Daghofer;F. Assaad
对准一维系统（如量子线和表面上的金属链）的实验表明，存在相当大范围的电子-电子相互作用，因此物理学超出了哈伯德模型。因此，我们通过量子蒙特卡罗方法和精确对角化研究了具有可变筛选长度的库仑势的一维四分之一填充链。Luttinger流体相互作用参数K_rho随相互作用强度和作用范围的增大而减小。实验观察到接近1/4的值需要强相互作用和/或较大的筛选长度。正如玻色子化所预测的那样，我们在K_rho=1/4处发现了金属-绝缘体跃迁。随着筛选长度的增加，电荷和自旋相关函数显示出从2k_F主导的自旋相关向4k_F主导的电荷相关的交叉，并且电荷速度有很强的增强。在金属相中，单粒子光谱中自旋-电荷分离的特征，自旋和全息带，即使在相当长的相互作用中也保持强劲。电荷密度波态呈现背向折叠的阴影带。
Experiments on quasi-one-dimensional systems such as quantum wires and metallic chains on surfaces suggest the existence of electron-electron interactions of substantial range and hence physics beyond the Hubbard model. We therefore investigate one-dimensional, quarter-filled chains with a Coulomb potential with variable screening length by quantum Monte Carlo methods and exact diagonalization. The Luttinger liquid interaction parameter K_rho decreases with increasing interaction strength and range. Experimentally observed values close to 1/4 require strong interactions and/or large screening lengths. As predicted by bosonization, we find a metal-insulator transition at K_rho=1/4. Upon increasing the screening length, the charge and spin correlation functions reveal the crossover from dominant 2k_F spin correlations to dominant 4k_F charge correlations, and a strong enhancement of the charge velocity. In the metallic phase, the signatures of spin-charge separation in the single-particle spectrum, spinon and holon bands, remain robust even for rather long-ranged interactions. The charge-density-wave state exhibits backfolded shadow bands.