Discovery of a Cooper-pair density wave state in a transition-metal dichalcogenide
Discovery of a Cooper-pair density wave state in a transition-metal dichalcogenide
复制标题
DOI：
10.1126/science.abd4607
复制
发表时间：
2021-06-25
期刊：
影响因子：
56.9
通讯作者：
Davis, J. C. Seamus
中科院分区：
文献类型：
--
作者：
Liu, Xiaolong;Chong, Yi Xue;Davis, J. C. Seamus
对密度波（PDW）态是由空间调制的双序参量定义的。为了在过渡金属二硫属化物（TMD）中寻找这种状态，我们使用了高速原子分辨率扫描约瑟夫森隧道显微镜。我们探测到一个PDW态，其电子对密度和能隙在空间上以预先存在的电荷密度波（CDW）态的波矢量进行调制。PDW线性耦合到s波超导体和CDW，并在边界处表现出具有离散相位滑移的公度域，符合晶格锁定的公度CDW。尽管如此，我们发现了一个全球性的delta φ全等的PDW和CDW状态之间的+/- 2 π/3相位差，可能是由于库珀对波函数轨道内容。我们的研究结果预示着普遍的PDW物理在许多其他TMD，维持CDW和超导状态。
Pair density wave (PDW) states are defined by a spatially modulating superconductive order parameter. To search for such states in transition-metal dichalcogenides (TMDs), we used high-speed atomicresolution scanned Josephson-tunneling microscopy. We detected a PDW state whose electron-pair density and energy gap modulate spatially at the wave vectors of the preexisting charge density wave (CDW) state. The PDW couples linearly to both the s-wave superconductor and the CDW and exhibits commensurate domains with discommensuration phase slips at the boundaries, conforming those of the lattice-locked commensurate CDW. Nevertheless, we found a global delta Phi congruent to +/- 2 pi/3 phase difference between the PDW and CDW states, possibly owing to the Cooper-pair wave function orbital content. Our findings presage pervasive PDW physics in the many other TMDs that sustain both CDW and superconducting states.