Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.29124

Magnetization and Josephson current coupling drives the Josephson diode effect in FeTe0.55Se0.45 van der Waals junctions

Seung-Hyun Shin·Cheong-Eung Ahn·Chang-Won Choi·Taekoo Oh·Si-Young Choi·Genda Gu·Gil Young Cho·Gil-Ho Lee
View original source ↗Read source document ↗Export metadata ↓

Abstract

The Josephson diode effect (JDE) reflects symmetry breaking in the current-phase relation (CPR) of Josephson junctions, yet establishing its microscopic origin is often challenging. We investigate the mechanism of the JDE in van der Waals Josephson junctions based on FeTe0.55Se0.45, a platform where superconductivity, topology, and magnetism may coexist at the interface. Our devices exhibit a robust zero-field diode response with asymmetric switching currents. Magnetic-field measurements reveal a hysteretic Fraunhofer pattern and magnetic-resonance-induced voltage feature, evidencing interfacial magnetism coupled to the Josephson current. Microwave response further shows half-integer Shapiro steps with asymmetric evolution, demonstrating contributions from both a second harmonic and a magnetization-induced phase shift in CPR. Numerical simulations combining magnetization dynamics and Josephson phase dynamics reproduce these features, confirming that the JDE originates from interfacial coupling between magnetization and Josephson current. This work provides a transport-based route to pinpoint the microscopic mechanism of the JDE, establishing a platform for exploring magnetically active interfacial superconductivity, and enables the design of nonreciprocal superconducting devices in clean, interface-engineered van der Waals systems.

Explore related subjects

cond-mat.supr-con

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Seung-Hyun Shin, Cheong-Eung Ahn, Chang-Won Choi, Taekoo Oh, Si-Young Choi, Genda Gu, Gil Young Cho, Gil-Ho Lee. 2026-10-21. Magnetization and Josephson current coupling drives the Josephson diode effect in FeTe0.55Se0.45 van der Waals junctions. https://arxiv.org/abs/2610.29124

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

KEEP EXPLORING

Related papers

arXiv2026

Josephson effect in symmetry-mismatched van der Waals hybrid junctions of NbSe2-Bi2Sr2CaCu2O8+x and NbSe2-Bi2Sr2-xLaxCuO6+y

Coupling superconductors of different symmetries may lead to emergent quantum phenomena but experimental studies on heterojunctions made of lattice-mismatched crystals are scarce. Here, we fabricate Josephson junction by van der Waals stacking NbSe2 flakes on freshly cleaved surfaces of Bi2Sr2CaCu2O8+x or Bi2Sr2-xLaxCuO6+y. We obtain pronounced Josephson currents across the heterojunctions at temperatures below 7 K. The Josephson coupling strength, characterized by the product of the critical Josephson current I_c and the normal state resistance R_n, can reach about 0.3 mV, much exceeding the values previously reported in Pb-Bi2Sr2CaCu2O8+x or Nb-Bi2Sr2CaCu2O8+x junctions. Microwave irradiation induces integer Shapiro steps. We also observe the Fraunhofer diffraction pattern by applying an in-plane magnetic field. We compare our results with the theoretical calculations that take into account the coherent tunneling and the order parameter mixing. Our work demonstrates the hybrid junctions as a distinctive platform for addressing pairing symmetry and emergent quantum phenomena.

cond-mat.supr-con↗
arXiv2026

Exotic vortex states and enhancement of orbital upper critical fields in an $s$-wave quasicrystalline superconductor

Quasicrystals possess long-range order without translational symmetry, giving rise to intrinsically inhomogeneous superconducting states. Using the Bogoliubov-de Gennes mean-field theory, we investigate vortex states in an $s$-wave quasicrystalline superconductor on the Ammann-Beenker tiling, with particular emphasis on the high-field regime. We find that the vortex configuration can differ qualitatively from the Abrikosov triangular lattice. In particular, at filling $ν=0.8$, vortices preferentially penetrate weak-pairing regions centered on sites with coordination number $8$, indicating that their spatial organization is strongly influenced by the local geometry. Furthermore, we observe an enhanced upper critical field. At $ν=0.8$, where the enhancement is particularly pronounced, the spatially averaged order parameter exhibits a plateau-like field dependence accompanied by the formation of vortex clusters. These clusters accommodate additional flux in locally weak superconducting regions, providing a microscopic interpretation of the plateau-like behavior. Moreover, the upper critical field increases upon cooling toward zero temperature without a clear sign of saturation.

cond-mat.supr-con↗
arXiv2026

Suppressing Majorana Hybridization in Atomically Assembled Cr Chains on Bi2Pd

Magnetic-atom chains on superconductors can host Majorana zero modes, but in finite chains the two end modes generally hibridize and split away from zero energy. We show that Cr chains assembled atom-by-atom on the Bi-terminated surface of Bi2Pd enter a short-localization-length Shiba chain regime wthat strongly suppreesses this finite-size hybridization. Scanning tunneling spectroscopy reveals a chaing-leght-driven closing and reopening of the in-gap spectrum, followed by zero-bias modes localized at the chains ends. Green-function calculations reproduce the evolution and show an exchange of electorn-holec haracter across the transition. From the residual splitting we extract a localization length of about three atomic sites, explaining the stability of the zero-energy modes in experimentally accessible chains.

cond-mat.supr-con↗