Work

Tunable second harmonic in altermagnetic Josephson junctions

Year: 2025

Type: article

Abstract: We study the influence of external electric and Zeeman fields on the Josephson effect in a planar superconductor/altermagnet/superconductor junction. Remarkably, we find that the current-phase relation (CPR) can be forward or backward skewed due to a pronounced second harmonic term. It decisively depends on the altermagnetic field strength. This second harmonic can be measured directly using double SQUID devices. The CPR skewness can be effectively manipulated by electric gating. Moreover, we identify two additional impacts of external electric and magnetic fields on the Josephson current: (i) Fields can induce 0-$\ensuremath{\pi}$ transitions. (ii) Fields can substantially enhance the critical current. This enhancement is surprising since supercurrents are typically suppressed by magnetic fields.

Source: Physical review. B./Physical review. B

DOI: 10.1103/physrevb.111.165406

Authors: Hai-Peng Sun, Song-Bo Zhang, Chang-An Li, Björn Trauzettel

Institutions: University of Würzburg, Complexity, Topology and Dynamics in Quantum Matter, Shenzhen Technology University, University of Science and Technology of China

Language: English

Topic: Physics of Superconductivity and Magnetism

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Deutsche Forschungsgemeinschaft, Bayerische Staatsministerium für Wirtschaft, Landesentwicklung und Energie

Awards: G2152757567, G2158694287, SFB 1170: Topologische und korrelierte Elektronik in Ober und Grenzflächen ("ToCoTronics"), G4955251027, EXC 2147: Komplexität und Topologie in Quantenmaterialien (CT.QMAT)