Abstract We present a theoretical model to show that the transition from an antiferromagnetic (AFM) phase to the d x 2 − y 2 -wave superconductivity occurs through a robust companion of a finite momentum pairing between ( k , ↑ ) and ( − k − Q , ↓ ) electrons, namely a pair-density wave (PDW) state, where Q = ( π , π ) is the AFM wavevector. Interestingly, the spatial structure of the PDW is constrained to be a p + i p -wave symmetry, which follows p k = p − k − Q under fermions exchange in cuprates, dictating a spin–singlet pairing. Furthermore, the PDW state produces a fully gapped quasiparticle spectrum which explains recent observations of the fully gapped quasiparticle structure of lightly doped cuprates in the hole doping side. We study the stability of all three phases within the self-consistent mean-field theory. Finally, we calculate the superfluid density to propose its exponential temperature dependence as a test to the superconducting origin of this fully gapped state, while the phase modulation of the PDW state can be visualized by scanning probes.

中文翻译：

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低掺杂铜酸盐中奇偶校验对密度波引起的无节点超导间隙

摘要 我们提出了一个理论模型来证明从反铁磁 (AFM) 相到 dx 2 − y 2 波超导性的转变是通过 ( k , ↑ ) 和 ( − k − Q , ↓ ) 电子，即对密度波 (PDW) 状态，其中 Q = ( π , π ) 是 AFM 波矢。有趣的是，PDW 的空间结构被限制为 ap + ip 波对称性，在铜酸盐中的费米子交换下遵循 pk = p − k − Q，决定了自旋-单重态配对。此外，PDW 状态产生了一个完全有隙的准粒子光谱，这解释了最近对空穴掺杂侧的轻掺杂铜酸盐的完全有隙的准粒子结构的观察。我们研究了自洽平均场理论中所有三个阶段的稳定性。最后，