论文标题
掺杂的多型哈伯德链中超导性的出现
Emergence of Superconductivity in Doped Multiorbital Hubbard Chains
论文作者
论文摘要
我们为一维二 - 轨道哈伯德模型引入了一个变异状态，该模型直观地解释了孔掺杂时这些系统中对配对的最新计算发现。我们的ANSATZ是Affleck-Kennedy-Lieb-Tasaki Valence键态的优化线性叠加，使该组合构成价值键液体配音轨道谐振价键。我们表明，两个位点的未息（一个电子/轨道）量子状态耦合到全球旋转式单线中，正好仅使用旋转1/2单旋风链接在最近的邻居位点上链接轨道。概括较长的链条定义了我们的变异状态可视化的几何形式，将我们的链条表示为两腿梯，每腿有一个轨道。就像在安德森（Anderson）的共鸣价键状态一样，我们未稳定的变分状态包含预先形成的单元对，通过掺杂变成移动性，导致超导性。带有一维子结构，两个近定位轨道的掺杂的真实材料，以及中间哈伯德u/w强度 - 载体的带宽 - 如果现场各向异性小，则可以意识到旋转的单词配对。如果这些各向异性稳健，则会出现自旋三型配对。
We introduce a variational state for one-dimensional two-orbital Hubbard models that intuitively explains the recent computational discovery of pairing in these systems when hole doped. Our Ansatz is an optimized linear superposition of Affleck-Kennedy-Lieb-Tasaki valence bond states, rendering the combination a valence bond liquid dubbed Orbital Resonant Valence Bond. We show that the undoped (one electron/orbital) quantum state of two sites coupled into a global spin singlet is exactly written employing only spin-1/2 singlets linking orbitals at nearest-neighbor sites. Generalizing to longer chains defines our variational state visualized geometrically expressing our chain as a two-leg ladder, with one orbital per leg. As in Anderson's resonating valence-bond state, our undoped variational state contains preformed singlet pairs that via doping become mobile leading to superconductivity. Doped real materials with one-dimensional substructures, two near-degenerate orbitals, and intermediate Hubbard U/W strengths -- W the carrier's bandwidth -- could realize spin-singlet pairing if on-site anisotropies are small. If these anisotropies are robust, spin-triplet pairing emerges.
