Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.24401

Second Chern Number Protected Gapless Vortex Modes in Superconducting Weyl Semimetals

Zhicheng Zhang·Jiangping Hu
View original source ↗Read source document ↗Export metadata ↓

Abstract

We have studied the vortex bound states of superconducting linear and quadratic Weyl semimetals with time reversal symmetry. For vortex with vorticity $n$ (vortex line along $z$ direction) and Weyl semimetals with Weyl point chirality $χ$, there are $\vert nχ\vert$ gapless vortex modes around the location of each Weyl point in superconducting Weyl semimetals. We show that the appearance of $\vert nχ\vert$ gapless vortex modes originates from the imbalanced pumping of flux bound states between Chern insulators obtained at $k_{z}$ and $-k_{z}$ in Weyl semimetals. Such a physical picture is verified by numerical calculations on lattice models. Moreover, the gapless modes around each Weyl point can be characterized by the second Chern number defined in a synthetic four-dimensional space based on the effective BdG Hamiltonian. Finally, these gapless vortex modes are found to be robust against rotational symmetry-breaking terms.

Explore related subjects

cond-mat.supr-concond-mat.mes-hall

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Zhicheng Zhang, Jiangping Hu. 2026-10-17. Second Chern Number Protected Gapless Vortex Modes in Superconducting Weyl Semimetals. https://arxiv.org/abs/2610.24401

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

KEEP EXPLORING

Related papers

arXiv2026

Gate-Switchable Josephson Diode Effect in Graphene via Magnetochiral Anisotropy

The Josephson diode effect originating from magnetochiral anisotropy has thus far been realized primarily in conventional two-dimensional electron gases. Here, we propose a graphene-based Josephson junction as a broadly gate-tunable platform for nonreciprocal supercurrent transport. We demonstrate that the nonreciprocal critical current not only reverses its sign when graphene is switched from $n$- to $p$-type doping via electrostatic gating, but its efficiency can also be continuously tuned from zero up to $\sim 40\%$. This gate-controlled polarity switching and efficiency modulation---unique to the chiral nature of Dirac fermions in graphene---has no counterpart in conventional semiconductor systems, positioning the graphene Josephson diode as a highly versatile component for advanced superconducting circuits.

cond-mat.supr-con↗
arXiv2026

Interaction and disorder effects on Cooper instability in two-dimensional fractional Dirac semimetals

Employing a renormalization group analysis that allows for an unbiased treatment of competing physical ingredients, we systematically trace how the interplay between Cooper pairing and disorder scatterings governs the emergence or suppression of Cooper instability in the low-energy regime of fractional Dirac semimetals.In the clean limit, we find that the emergence of Cooper instability requires surpassing a finite interaction threshold $|λ_c|$, and depends sensitively on both the fractional exponent $α$ and the transfer momentum $\mathbf{Q}=(Q,ϕ)$. Specifically, bigger values of $α$ enhance the tendency toward BCS instability. For $α\in(0.001,0.61)$, the $(Q,ϕ)$ parameter space separates into two distinct regions: Zone-\uppercase\expandafter{\romannumeral1}, where Cooper instability is suppressed, and Zone-\uppercase\expandafter{\romannumeral2}, where it is allowed. In the presence of disorders, we demonstrate that they can either promote or suppress Cooper instability. Disorder of type $Δ_1$ or $Δ_2$ enhances superconductivity by reducing the critical interaction threshold $|λ_c|$ and expanding the superconducting phase space (Zone-\uppercase\expandafter{\romannumeral2}). In sharp contrast, either $Δ_0$ or $Δ_3$ suppresses Cooper pairing by increasing $|λ_c|$ and shrinking the available phase space (Zone-\uppercase\expandafter{\romannumeral1}). Although Cooper instability can be enhanced when promotive disorders ($Δ_1$, $Δ_2$) coexist with a single suppressive disorder ($Δ_0$ or $Δ_3$), the suppressive influence of $Δ_{0,3}$ generally dominates the promotive effects of $Δ_{1,2}$ in the presence of all sorts of disorders. These results would be helpful for further studies of fractional Dirac semimetals and alike materials.

cond-mat.supr-con↗
arXiv2026

Relaxation Dynamics of Superconducting/Normal Interfaces in the Intermediate State of a type-I superconductor

The dynamics of phase boundaries, such as superconducting/normal (S/N) interfaces in type-I superconductors, are typically obscured in conventional magnetic measurements, which are strongly influenced by surface barriers and global flux processes. Here, we employ the complex ac magnetostrictive coefficient as a sensitive probe of the bulk dynamics of S/N interfaces in the intermediate state of lead. The ac magnetostrictive coefficient exhibits an unusual complex response, with a negative real component and a positive imaginary component. Frequency-dependent measurements show that the magnitude of the real component decreases monotonically with increasing frequency, whereas the imaginary component first increases, reaches a broad maximum, and then decreases. In contrast, ac susceptibility displays a conventional Debye-type magnetic relaxation with a different phase relation between its real and imaginary components. We propose that the magnetostrictive response arises from ac-field-driven relaxation and rearrangement of metastable S/N domain configurations toward states of lower free energy. These results reveal a distinct interfacial relaxation channel in the intermediate state and establish the complex ac magnetostrictive coefficient as a sensitive probe of nonequilibrium S/N interface dynamics.

cond-mat.supr-con↗