AI 中文总结
研究电子掺杂莫特绝缘体中低能单粒子激发的不对称性，通过确定\(t\) - \(t'\) - \(J\)模型基态波函数的双组分结构，利用变分蒙特卡罗方法揭示不同掺杂下激发差异，提出唯象格林函数与实验相符。
AI 中文摘要
实验研究揭示了电子掺杂和空穴掺杂铜酸盐在低能单粒子激发方面存在显著不对称性。电子掺杂铜酸盐呈现出非平凡的二分法：费米液体行为（表明电子关联较弱）与空穴掺杂系统典型的关联驱动特征共存。本工作通过确定\(t\) - \(t'\) - \(J\)模型的基态波函数一般具有双组分结构来解决此问题，该结构由相干准粒子和非相干复合组分组成。动能源于相干准粒子的本征传播以及这些组分之间的共振。通过单空穴水平的变分蒙特卡罗方法，我们表明对于空穴掺杂（\(t'<0\)），组分间的这种共振占主导并集中在低能的节点区域。这种由共振引起的新兴传播可物理地解释为源于分数化自由度的复合，从而驱动了与强关联相关的各种现象。相反，对于电子掺杂（\(t'>0\)），具有费米液体常规性质的相干准粒子传播在低能的反节点区域被选择性增强。这在电子掺杂系统的动量空间中产生了分离：低能下的反节点谱权重由相干准粒子主导，与仍由非相干复合组分主导的节点区域有根本不同。受这种结构的启发并在实验观察的指导下，我们提出了有限掺杂下的唯象格林函数，其谱特征与实验一致。
英文摘要
Experimental studies reveal a striking asymmetry in low-energy single-particle excitations between electron- and hole-doped cuprates. Electron-doped cuprates display a nontrivial dichotomy: Fermi-liquid-like behavior (suggesting weaker electronic correlations) coexists with correlation-driven features typical of hole-doped systems. This dual nature challenges a unified description within a doped Mott insulator framework. The present work addresses this issue by establishing that the ground-state wave function of the $t$-$t'$-$J$ model generically possesses a two-component structure, comprising a coherent quasiparticle and an incoherent composite component. The kinetic energy arises from both the intrinsic propagation of the coherent quasiparticle and the resonance between these components. Using variational Monte Carlo at the level of a single hole, we show that for hole doping ($t'<0$), this resonance between components dominates and concentrates in the nodal region at low energies. This emergent propagation induced by resonance can be physically interpreted as originating from the recombination of fractionalized degrees of freedom, which drives various phenomena associated with strong correlations. Conversely, for electron doping ($t'>0$), the coherent quasiparticle propagation, which exhibits conventional properties of a Fermi liquid, is selectively enhanced in the antinodal region at low energies. This produces a separation in momentum space for systems with electron doping: the antinodal spectral weight at low energies is governed by the coherent quasiparticle, fundamentally differing from the nodal region, which remains dominated by the incoherent composite component. Motivated by such a structure and guided by experimental observations, we propose a phenomenological Green's function at finite doping, yielding spectral features consistent with experiments.
Comments28 pages, 13 figures
