NATURE
·
2023
·Vol. 617
·期 7961
·488-492
·
IF 64.8
Zhong Yigui,Liu Jinjin,Wu Xianxin,Guguchia Zurab,Yin J.-X.,Mine Akifumi,Li Yongkai,Najafzadeh Sahand,Das Debarchan,Mielke Charles,Khasanov Rustem,Luetkens Hubertus,Suzuki Takeshi,Liu Kecheng,Han Xinloong,Kondo Takeshi,Hu Jiangping,Shin Shik,Wang Zhiwei,Shi Xun,Yao Yugui,Okazaki Kozo
The newly discovered kagome superconductors represent a promising platform for investigating the interplay between band topology, electronic order and lattice geometry 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . Despite extensive research efforts on this system, the nature of the superconducting ground state remains elusive 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 . In particular, consensus on the electron pairing symmetry has not been achieved so far 18 , 19 , 20 , in part owing to the lack of a momentum-resolved measurement of the superconducting gap structure. Here we report the direct observation of a nodeless, nearly isotropic and orbital-independent superconducting gap in the momentum space of two exemplary CsV 3 Sb 5 -derived kagome superconductors—Cs(V 0.93 Nb 0.07 ) 3 Sb 5 and Cs(V 0.86 Ta 0.14 ) 3 Sb 5 —using ultrahigh-resolution and low-temperature angle-resolved photoemission spectroscopy. Remarkably, such a gap structure is robust to the appearance or absence of charge order in the normal state, tuned by isovalent Nb/Ta substitutions of V. Our comprehensive characterizations of the superconducting gap provide indispensable information on the electron pairing symmetry of kagome superconductors, and advance our understanding of the superconductivity and intertwined electronic orders in quantum materials.
研究领域:
凝聚态物理
·
超导物理
·
电子结构
·
量子材料
✓ 已验证
DOI
高影响因子
Scientific Reports
·
2024
·Vol. 14
·期 1
·9580
·
IF 3.8
Liu Jinjin,Li Qing,Li Yongkai,Fan Xinwei,Li Jun,Zhu Peng,Deng Hanbin,Yin Jia-Xin,Yang Huaixin,Li Jianqi,Wen Hai-Hu,Wang Zhiwei
Kagome superconductors AV 3 Sb 5 (A = K, Rb, and Cs) have attracted enormous interest due to the coexistence of charge density wave (CDW) order, unconventional superconductivity (SC) and anomalous Hall effect (AHE). In this paper, we reported an intensive investigation on Cs(V 1− x Ta x ) 3 Sb 5 single crystals with systematic Ta doping. Ta was confirmed to be doped into V-site in the Kagome layer from both single crystal X-ray diffraction structural refinement and scanning transmission electron microscopy observation. The highest Ta doping level was found to be about 16%, which is more than twice as much as 7% in Nb-doped CsV 3 Sb 5 . With the increase of Ta doping, CDW order was gradually suppressed and finally vanished when the doping level reached to more than 8%. Meanwhile, superconductivity was enhanced with a maximum critical temperature ( T c) of 5.3 K, which is the highest T c in the bulk crystal of this Kagome system at ambient pressure so far. The μ 0 H c2 (T) behavior demonstrates that the system is still a two-band superconductor after Ta doping. Based on the electrical transport measurement, a phase diagram was set up to exhibit the evolution of CDW and SC in the Cs(V 1− x Ta x ) 3 Sb 5 system. These findings pave a new way to search for new superconductors with higher T c in the AV 3 Sb 5 family and establish a new platform for tuning and controlling the multiple orders and superconducting states.
研究领域:
凝聚态物理
·
超导物理
·
量子材料
·
强关联电子体系
·
晶体生长
✓ 已验证
DOI
高影响因子
Science Advances
·
2025
·Vol. 11
·期 38
·
IF 12.5
Xiangkai Meng,Chong Wang,Maoyuan Wang,Jinjin Liu,Pai Zhou,Qiaoxia Xing,Yuqing Zheng,Haochen Zhang,Wenqi Bi,Hanchao Teng,Jianhui Zhou,Jun Li,Zhiwei Wang,Hai Hu,Qing Dai,Hugen Yan,Yugui Yao
Van Hove singularities (VHSs) play a critical role in determining the properties of topological and correlated electronic states. Their associated excitations offer unique opportunities for exploring light-matter interactions reshaped by these correlated states, although experimental observations remain limited. Here, we studied the interaction between plasmons and VHS-related excitations in kagome metal CsV 3 Sb 5 films via far-field absorption spectroscopy. Notably, an anticrossing phenomenon was observed in the charge density wave states, with coupling strength approaching the strong coupling regime, indicating the formation of dispersive hybrid VHS interband plasmons. These modes are closely correlated to charge ordering states, with both the fitted coupling strength and the universal screening length of interband transitions exhibiting pronounced anomalies at the transition temperature. Our findings offer critical insights into the role of correlated electronic states in modulating plasmon behavior in kagome metals and unveil promising possibilities for tuning light-matter interactions in correlated materials.
研究领域:
凝聚态物理
·
等离激元学
·
量子材料
·
强关联电子系统
·
拓扑材料
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）