Abstract
Kagome metals (, Rb, and Cs) exhibit a unique superconducting ground state coexisting with charge-density wave (CDW), whereas how these characteristics are affected by carrier doping remains unexplored because of the lack of an efficient carrier-doping method. Here we report successful electron doping to by Cs dosing, as visualized by angle-resolved photoemission spectroscopy. We found that the electron doping with Cs dosing proceeds in an orbital-selective way, as characterized by a marked increase in electron filling of the Sb and V bands as opposed to the relatively insensitive nature of the V bands. By monitoring the temperature evolution of the CDW gap around the point, we found that the CDW can be completely killed by Cs dosing while keeping the saddle point with the V character almost pinned at the Fermi level. The present result suggests a crucial role of multiorbital effect to the occurrence of CDW and provides an important step toward manipulating the CDW and superconductivity in .
- Received 8 May 2021
- Revised 22 September 2021
- Accepted 8 November 2021
DOI:https://doi.org/10.1103/PhysRevX.12.011001
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
When atoms are arranged in corner-sharing triangles, a geometrically special structure known as a kagome lattice is formed, in which exotic electronic and magnetic properties are predicted. Examples include superconductivity, relativistic electron motion, and quantum entanglement of electron spin. Such properties are sensitive to the concentration of electrons in the crystal, so tuning that concentration is crucial for not only exploring and controlling the exotic properties but also understanding the underlying physical mechanisms. Here, we develop a convenient means to introduce electron carriers into a newly discovered superconductor with a kagome lattice and realize a drastic change in the electronic properties.
We focus on the kagome material , in which superconductivity coexists with a spatial modulation of electron charge density called a charge-density wave. To introduce additional charge carriers, we dose cesium atoms onto the crystal surface. By monitoring the evolution of the electronic structure using angle-resolved photoemission spectroscopy, we demonstrate a heavy electron-doping effect, which has never been realized in this material’s family. We further show complete suppression of the charge-density wave, triggered by an unusual orbital-selective change in the electronic structure. This finding suggests that the electrons in multiple atomic orbitals are simultaneously involved in the occurrence of the charge-density wave.
Our observation lays a foundation for understanding the nature of charge-density waves and their interplay with superconductivity in . In addition, our carrier-tuning technique would be useful to explore superconductivity at even higher temperatures.