Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.16253

Pressure Evolution of the Superconducting Order Parameter of Kagome Superconductor CsV3Sb5

Haiyan Zuo·Wangju Yang·Zhifan Wu·Yuqing Zhao·Qiuxia Chen·Weiming Lao·Yangpeng Qi·Hechang Lei·Haizi Cong·Cong Ren
View original source ↗Read source document ↗Export metadata ↓

Abstract

Kagome superconductors AV3Sb5 (A = K, Rb, Cs) offer an outstanding platform for exploring the interplay among charge-density-wave (CDW) order, superconductivity (SC), and nontrivial topological electronic states. For CsV3Sb5, moderate hydrostatic pressure induces a double-dome superconducting phase diagram while monotonically suppressing the CDW phase, which signals an unconventional coupling between SC and CDW. Nevertheless, the microscopic nature of the pressure-modulated superconducting state and its relationship with CDW order remain poorly understood. Here we employ soft directional point-contact spectroscopy (SDPCS), combined with superconducting resistive measurements, to probe the superconducting order parameter of CsV3Sb5 under hydrostatic compression. Our anisotropic PCAR measurements resolve two distinct s-wave superconducting gaps along the c-axis and a strongly anisotropic gap within the ab plane. Two-band Blonder-Tinkham-Klapwijk (BTK) fits to the c-axis spectra yield a large gap satisfying 2Delta1/kBTc > 3.52 and a small gap with 2Deltas/kBTc < 3.52. The spectral-weight-averaged coupling ratio 2Deltaavg/kBTc is enhanced in the pressure window between P1 and P2, suggesting that pressure-induced modifications of the low-energy electronic structure may contribute to the evolution of superconductivity. For ab-plane junctions, the superconducting gap anisotropy is gradually suppressed above P1, accompanied by the emergence of a pronounced peak-dip-hump structure suggestive of enhanced coupling between superconducting quasiparticles and a bosonic excitation. These results shed new light on the intricate entanglement between CDW and SC in kagome superconductivity.

Explore related subjects

cond-mat.supr-con

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Haiyan Zuo, Wangju Yang, Zhifan Wu, Yuqing Zhao, Qiuxia Chen, Weiming Lao, Yangpeng Qi, Hechang Lei, Haizi Cong, Cong Ren. 2026-10-12. Pressure Evolution of the Superconducting Order Parameter of Kagome Superconductor CsV3Sb5. https://arxiv.org/abs/2610.16253

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Ultrasmall (3,0) carbon nanotube: a superconducting unit with strong electron-phonon coupling

Based on density-functional first-principles calculations, we study the electronic structures, lattice dynamics, and electron-phonon coupling (EPC) properties of the ultrasmall one-dimensional (3,0) carbon nanotube (CNT). Our studies reveal that the (3,0) CNT hosts characteristic collective phonon modes, in which the corresponding atomic vibrations can significantly modulate the electronic self-consistent potential and induce strong EPC. Our results further show that the (3,0) CNT exhibits robust phonon-mediated superconductivity under ambient pressure, with a superconducting transition temperature reaching $\sim$ 33 K ($μ^*$ = 0.10). We also find that although hole doping enhances the density of states (DOS) near the Fermi level, it simultaneously hardens the strongly coupled phonon modes and suppresses the total EPC. This result indicates that phonons play a more crucial role in the superconductivity of ultrasmall CNTs rather than the DOS alone. Therefore, we suggest that the ultrasmall (3,0) CNT can serve as a superconducting unit hosting phonon modes with strong EPC, and propose a strategy for discovering new phonon-mediated superconductors by identifying superconducting units.

cond-mat.supr-con↗
arXiv2026

In-Plane Differentiation and Out-of-Plane Coherence in Superconducting K$_{2-x}$Fe$_{4+y}$Se$_5$

The structural link between superconductivity and anomalous $d_2$ diffraction signatures in K$_{2-x}$Fe$_{4+y}$Se$_5$ remains unresolved. Their appearance is accompanied by pronounced host-lattice evolution rather than a static structural background. Using high-resolution synchrotron X-ray diffraction, we show that excess Fe alters the vacancy-ordered host lattice, with structural differences between superconducting and nonsuperconducting states emerging before the $d_2$ features appear. All observed $d_2$ reflections can be described using two characteristic in-plane spacings and a nearly common low-temperature $c$ parameter. Temperature-dependent measurements reveal that superconductivity is associated with persistent in-plane differentiation and enhanced Fe-layer coherence along the $c$ axis. These results establish host-lattice evolution as the common structural origin linking the $d_2$ family and superconductivity, and suggest that the host-lattice differentiation identified here represents a structural analogue of the symmetry redistribution in FeSe.

cond-mat.supr-con↗
arXiv2026

Correlation-driven enhancement of pairing in a nematic Hund's metal

Superconductivity and nematicity coexist in the phase diagram of many correlated systems, including iron-based superconductors. We investigate how Hund-driven correlations reshape boson-mediated superconductivity in a multiorbital nematic metal. We find that dynamical correlation effects beyond a quasiparticle-only description are essential to capture the robustness of superconductivity in the Hund regime. In the nematic phase, Hund correlations simultaneously enhance the orbital differentiation of the superconducting gaps and inhibit the most extreme nematic-driven orbital polarization and coherence collapse that would otherwise suppress pairing at strong coupling. A controlled cutoff analysis reveals a nontrivial, orbital-dependent buildup of the gaps, indicating that different frequency windows of the correlated spectrum contribute unevenly to pairing in the nematic Hund regime. This implies that pairing mechanisms with different characteristic boson energies can lead to distinct gap structures and trends.

cond-mat.supr-con↗