Gao Jianhua, Park Jae Whan, Kim Kiseok, Song Sun Kyu, Park Hae Ryong, Lee Jhinhwan, Park Jewook, Chen Fangchu, Luo Xuan, Sun Yuping, Yeom Han Woong
Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Korea.
Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea.
Nano Lett. 2020 Sep 9;20(9):6299-6305. doi: 10.1021/acs.nanolett.0c01607. Epub 2020 Aug 6.
We investigate electronic states of Se-substituted 1-TaS by scanning tunneling microscopy/spectroscopy (STM/STS), where superconductivity emerges from the unique Mott-charge-density-wave (Mott-CDW) state. Spatially resolved STS measurements reveal that a pseudogap replaces the Mott gap with the CDW gaps intact. The pseudogap has little correlation with the unit-cell-to-unit-cell variation in the local Se concentration but appears globally. The correlation length of the local density of states (LDOS) is substantially enhanced at the Fermi energy and decays rapidly at high energies. Furthermore, the statistical analysis of LDOS indicates the weak multifractal behavior of the wave functions. These findings suggest a correlated metallic state induced by disorder and provide a new insight into the emerging superconductivity in two-dimensional materials.
我们通过扫描隧道显微镜/光谱（STM/STS）研究了硒取代的1-TaS的电子态，其中超导性源于独特的莫特电荷密度波（Mott-CDW）态。空间分辨的STS测量表明，一个赝能隙取代了莫特能隙，而CDW能隙保持完整。赝能隙与局部硒浓度在晶胞到晶胞之间的变化几乎没有关联，而是全局出现。在费米能处，局部态密度（LDOS）的关联长度显著增强，而在高能处迅速衰减。此外，对LDOS的统计分析表明波函数具有弱多重分形行为。这些发现表明了由无序诱导的关联金属态，并为二维材料中出现的超导性提供了新的见解。
