Fate of pairing and spin-charge separation in the presence of long-range antiferromagnetism
Fate of pairing and spin-charge separation in the presence of long-range antiferromagnetism
复制标题
DOI：
10.1103/physrevb.105.195104
复制
发表时间：
2021-10
影响因子：
3.7
通讯作者：
Luhang Yang;I. Hamad;L. Manuel;A. Feiguin
中科院分区：
文献类型：
--
作者：
Luhang Yang;I. Hamad;L. Manuel;A. Feiguin
本文对具有长程RKKY交错自旋相互作用的一维t-J模型中的竞争序进行了数值研究。通过绕过Mermin-Wagner定理的限制，该哈密顿量可以在半填充时实现长程N\'eel序.我们使用密度矩阵重整化群（DMRG）方法确定作为交换和粒子密度的函数的全相图。我们发现，配对是不利的，AFM绝缘体和金属相分离的广泛制度与相分离，在低密度下重新出现自旋-电荷分离之前。在掺杂时，相互作用诱导一个约束势，该约束势将holon和spinon约束成在一定参数和密度范围内的完全成熟的费米子准粒子。我们数值计算的光电子能谱的模型，显示出一个相干准粒子带分裂离开的holon-spinon连续的宽度由J$，生存在有限的掺杂。与使用自洽玻恩近似（SCBA）和通过解决自旋-holon问题的分析结果的比较提供了洞察准粒子的内部结构，并帮助我们解释光谱中的不同特征。我们将讨论这个简单的玩具模型如何教导我们关于它的高维对应物的现象学。
We present a numerical study of competing orders in the 1D $t$-$J$ model with long-range RKKY-like staggered spin interactions. By circumventing the constraints imposed by Mermin-Wagner's theorem, this Hamiltonian can realize long-range N\'eel order at half-filling. We determine the full phase diagram as a function of the exchange and particle density using the density matrix renormalization group (DMRG) method. We show that pairing is disfavored and the AFM insulator and metallic phases are separated by a broad regime with phase segregation, before spin-charge separation re-emerges at low densities. Upon doping, interactions induce a confining potential that binds holons and spinons into full fledged fermionic quasi-particles in a range of parameters and densities. We numerically calculate the photoemission spectrum of the model, showing the appearance of a coherent quasi-particle band splitting away from the holon-spinon continuum with a width determined by $J$ that survives at finite doping. Comparison with analytical results using the self-consistent Born approximation (SCBA) and by solving the spinon-holon problem offer insight into the internal structure of the quasi-particles and help us explain the different features in the spectrum. We discuss how this simple toy-model can teach us about the phenomenology of its higher dimensional counterpart.