2000/08/31 by Tomas Löfwander, T. Lofwander, V. S. Shumeĭko +3 · 41 citations
Materials Science · Mathematics · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Geometry #Iron-based superconductors research #Josephson effect #Josephson energy #Josephson phase #Mathematics #Physics #Physics of Superconductivity and Magnetism #Pi Josephson junction #Quantum mechanics #Superconductivity #Symmetry (geometry) #Symmetry breaking #T-symmetry #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.62.r14653
published in Physical review. B, Condensed matter 62(22), R14653-R14656 (American Physical Society) · 5 pages, 2 figures embedded; rewritten introduction
arxiv created 2000/10/16 · openalex publication_date 2000/12/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study spontaneous time-reversal symmetry breaking at Josephson tunnel junctions of d-wave superconductors in the absence of subdominant components of the order parameter. For tunnel junctions, when the orientation is close to 0/45 (for which a gap lobe points towards the junction on one side and a gap node on the other), the mechanism of the symmetry breaking is the splitting of midgap states (MGS) by spontaneous establishment of a phase difference \ensuremathφ=\ifmmode±\else\textpm\fi\ensuremathπ/2 across the junction. This occurs for transparencies D\ensuremath≫\ensuremathξ0/\ensuremathλ and temperatures kBT\ensuremath≪D\ensuremathΔ0, where \ensuremathξ0 is the coherence length, \ensuremathλ is the penetration depth, and \ensuremathΔ0 is the maximum energy gap. On the other hand, tunnel junctions with D\ensuremath≪\ensuremathξ0/\ensuremathλ effectively behave as surfaces, for which the mechanism of symmetry breaking is self-induced Doppler shifts of MGS. For this instability, we calculate the phase-transition temperature kBTTRSB=(1/6)(\ensuremathξ0/\ensuremathλ)\ensuremathΔ0 and show that the spatial shape of the gap is unimportant.