发表机构
Stanford University; The Graduate Center, CUNY; College of Staten Island, CUNY; SLAC National Accelerator Laboratory（斯坦福大学; 纽约市立大学研究生中心; 纽约市立大学斯塔顿岛学院; 斯坦福直线加速器中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过精确对角化在无限U Hubbard模型中验证了不良金属性源于强局域关联，发现半量子区域中电阻率呈T线性并超过Ioffe--Regel极限，伴随自旋笼形成，与多种材料行为相似。
AI 中文摘要
不良金属表现出超越Ioffe--Regel极限的近似$T$线性的直流电阻率。这种行为出现在基态截然不同的系统中，表明它是强局域关联的普遍表现。我们通过精确对角化计算有限团簇的热力学和输运性质，在小空穴密度下的无限$U$ Hubbard模型中检验这一假设。冷却时，我们发现一个中间温度范围，即液氦“半量子区域”的电子类似物，在该范围内量子效应产生近似与$T$无关的压缩率，但电阻率是$T$线性的并超过Ioffe--Regel极限。进入该区域伴随着掺杂空穴周围准局域铁磁“自旋笼”的形成，这些区域促进嵌入在涨落自旋背景中的局域量子运动，类似于被认为控制半量子液氦中非相干输运的瞬态晶体笼。值得注意的是，尽管模型简单，这里发现的不良金属行为与在各种材料平台中观察到的行为相似。
英文摘要
Bad metals exhibit approximately $T$-linear dc resistivity beyond the Ioffe--Regel limit. That this behavior occurs in systems with radically different ground states suggests it is a generic manifestation of strong local correlations. We test this hypothesis in the infinite-$U$ Hubbard model with small hole densities using exact diagonalization to compute thermodynamic and transport properties of finite clusters. Upon cooling, we find an intermediate temperature range, an electronic analogue of the ``semi-quantum regime'' of liquid helium, in which quantum effects produce a roughly $T$-independent compressibility, yet the resistivity is $T$-linear and exceeds the Ioffe--Regel limit. Entry into this regime is accompanied by the formation of quasi-local ferromagnetic ``spin cages'' around doped holes, regions that facilitate local quantum motion embedded in a fluctuating spin background, analogous to the transient crystalline cages thought to control incoherent transport in semi-quantum liquid helium. Remarkably, despite the simplicity of the model, the bad metal behavior found here resembles that seen in various material platforms.
Commentsmain text: 13 pages, 5 figures; SM: 21 pages, 8 figures
