Emergent charge order and unconventional superconductivity in pressurized kagome superconductor CsV3Sb5

TL;DR

This study investigates how pressure influences charge density waves and superconductivity in CsV3Sb5, revealing a new stripe-like CDW phase and unconventional pairing, advancing understanding of emergent phenomena in kagome superconductors.

Contribution

It uncovers a pressure-induced stripe-like CDW phase and details the interplay between charge order and superconductivity in CsV3Sb5 using nuclear magnetic resonance measurements.

Findings

Emergent stripe-like CDW phase between 0.58 GPa and 2.0 GPa.

Two-dome-like superconducting behavior under pressure.

Evidence for unconventional superconducting pairing above 2.0 GPa.

Abstract

The discovery of multiple electronic orders in kagome superconductors AV3Sb5 (A = K, Rb, Cs) provides a promising platform for exploring unprecedented emergent physics. Under moderate pressure (< 2.2 GPa), the triple-Q charge density wave (CDW) order is monotonically suppressed by pressure, while the superconductivity displays a two-dome-like behavior, suggesting an unusual interplay between superconductivity and CDW order. Given that time-reversal symmetry breaking and electronic nematicity have been revealed inside the triple-Q CDW phase, understanding this CDW order and its interplay with superconductivity becomes one of the core questions in AV3Sb5. Here, we report the evolution of CDW and superconductivity with pressure in CsV3Sb5 by 51V nuclear magnetic resonance measurements. An emergent CDW phase, ascribed to a possible stripe-like CDW order with a unidirectional 4a0 modulation, is observed between Pc1 ~ 0.58 GPa and Pc2 ~ 2.0 GPa, which explains the two-dome-like superconducting behavior under pressure. Furthermore, the nuclear spin-lattice relaxation measurement reveals evidence for pressure-independent charge fluctuations above the CDW transition temperature and unconventional superconducting pairing above Pc2. Our results not only shed new light on the interplay of superconductivity and CDW but also reveal novel electronic correlation effects in kagome superconductors AV3Sb5.