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Sign structure in the square-lattice $t$-$t^\prime$-$J$ model and numerical consequences
arXiv - PHYS - Superconductivity Pub Date : 2023-03-23 , DOI: arxiv-2303.13498
Xin Lu, Jia-Xin Zhang, Shou-Shu Gong, D. N. Sheng, Zheng-Yu Weng

Understanding the doped Mott insulator is a central challenge in condensed matter physics. This study identifies an intrinsic Berry-phase-like sign structure for the square-lattice $t$-$t'$-$J$ model with the nearest-neighbor ($t$) and next-nearest-neighbor hopping ($t'$), which could help explain the origin of the quasi-long-range superconducting and stripe phases observed through density matrix renormalization group (DMRG) calculation. We first demonstrate that the hole binding underlies both the superconducting and stripe orders, and then show that the hole pairing generically disappears once the phase-string or mutual statistics component of the sign structure is switched off in DMRG calculation. In the latter case, the superexchange interaction no longer plays a crucial role in shaping the charge dynamics, where a Fermi-liquid-like phase with small hole Fermi pockets is found. It is in sharp contrast to the large Fermi surfaces in either the stripe phase found at $t'/t<0$ or the superconducting phase at $t'/t>0$ in the original $t$-$t'$-$J$ model on the 6-leg ladder.

中文翻译:

方格 $t$-$t^\prime$-$J$ 模型中的符号结构和数值结果

理解掺杂的莫特绝缘体是凝聚态物理学的核心挑战。本研究确定了方格 $t$-$t'$-$J$ 模型的内在 Berry 相符号结构,具有最近邻 ($t$) 和次最近邻跳跃 ($t) '$), 这有助于解释通过密度矩阵重整化群 (DMRG) 计算观察到的准长程超导和条纹相的起源。我们首先证明空穴结合是超导和条纹顺序的基础,然后表明一旦符号结构的相位串或互统计组件在 DMRG 计算中关闭,空穴配对通常就会消失。在后一种情况下,超交换相互作用不再在塑造电荷动力学方面发挥关键作用,其中发现了带有小孔费米袋的类费米液体相。它与原始 $t$-$t'$ 中 $t'/t<0$ 处的条纹相或 $t'/t>0$ 处的超导相中的大费米面形成鲜明对比$J$ 模型在 6 腿梯子上。
更新日期:2023-03-24
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