Doping evolution of superconductivity, charge order and band topology in hole-doped topological kagome superconductors Cs(V${}_{1-x}$Ti${}_x$)${}_3$Sb${}_5$

Abstract

The newly discovered Kagome superconductors $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, Cs) exhibit superconductivity, charge order, and band topology simultaneously. To explore the intricate interplay between the superconducting and charge orders, we investigate the doping evolution of superconductivity, charge-density-wave (CDW) order, and band topology in doped topological kagome superconductors Cs(V${}_{1-x}$Ti${}_x$)${}_3$Sb${}_5$ where the Ti-dopant introduces hole-like charge carriers. Despite the absence of the CDW phase transition in doped compounds even for the lowest doping level of $x=0.047$, the superconductivity survives in all doped samples with enhanced critical temperatures. The high-resolution angle-resolved photoemission spectroscopy (ARPES) measurements reveal that the Ti-dopant in the kagome plane lowers the chemical potential, pushing the van Hove singularity (VHS) at $M$ point above the Fermi level. First-principle simulations corroborate the doping evolution of the band structure observed in ARPES, and affirm that the CDW instability does not occur once the VHS is pushed above the Fermi level, explaining the absence of the CDW ordering in our doped samples Cs(V${}_{1-x}$Ti${}_x$)${}_3$Sb${}_5$. Our results demonstrate a competition between the CDW and superconducting orders in the kagome-metal superconductor CsV${}_3$Sb${}_5$, although the superconductivity is likely inconsequential of the CDW order.

6 pages and 4 figures

References in corpus (6)

• High temperature fractional quantum Hall states
• Theory of Intertwined Orders in High Temperature Superconductors
• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Fermi surface nesting and the origin of Charge Density Waves in metals
• Unconventional Fermi surface instabilities in the Kagome Hubbard Model
• Valence Bond Solids and Their Quantum Melting in Hard-Core Bosons on the Kagome Lattice

Cited by in corpus (8)

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• Tuning charge-density wave order and superconductivity in the kagome metals KV${}_3$Sb${}_{5-x}$Sn${}_x$ and RbV${}_3$Sb${}_{5-x}$Sn${}_x$
• Electronic properties of correlated kagomé metals AV${}_3$Sb${}_5$(A = K, Rb, Cs): A perspective
• Superconducting, topological and transport properties of kagome metals CsTi${}_3$Bi${}_5$ and RbTi${}_3$Bi${}_5$
• Dirac Nodal Lines and Nodal Loops in a Topological Kagome Superconductor CsV${}_3$Sb${}_5$
• Topological superconductivity and large spin Hall effect in the kagome family Ti6X4 (X = Bi, Sb, Pb, Tl, In)
• Electrical and thermal transport properties of kagome metals AV${}_3$Sb${}_5$ (A=K, Rb, Cs)