Year: 2017
Type: article
Abstract: We study Josephson currents between $s$-wave/spin-triplet superconductor junctions by taking into account details of the band structures in ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$, such as three conduction bands and spin-orbit interactions in the bulk and at the interface. We assume five superconducting order parameters in ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$: a chiral $p$-wave symmetry and four helical $p$-wave symmetries. We calculate the current-phase relationship $I(\ensuremath{\varphi})$ in these junctions, where $\ensuremath{\varphi}$ is the macroscopic phase difference between the two superconductors. The results for a chiral $p$-wave pairing symmetry show that a $cos(\ensuremath{\varphi})$ term appears in the current-phase relation because of time-reversal symmetry (TRS) breaking. On the other hand, this $cos(\ensuremath{\varphi})$ term is absent in the helical pairing states that preserve TRS. We also study the dependence of the maximum Josephson current ${I}_{c}$ on an external magnetic flux $\mathrm{\ensuremath{\Phi}}$ in a corner junction. The calculated ${I}_{c}(\mathrm{\ensuremath{\Phi}})$ obeys ${I}_{c}(\mathrm{\ensuremath{\Phi}})\ensuremath{\ne}{I}_{c}(\ensuremath{-}\mathrm{\ensuremath{\Phi}})$ in a chiral state and ${I}_{c}(\mathrm{\ensuremath{\Phi}})={I}_{c}(\ensuremath{-}\mathrm{\ensuremath{\Phi}})$ in a helical state. We calculate ${I}_{c}(\mathrm{\ensuremath{\Phi}})$ in a corner superconducting quantum interference device (SQUID) and a symmetric SQUID geometry. In the latter geometry, ${I}_{c}(\mathrm{\ensuremath{\Phi}})={I}_{c}(\ensuremath{-}\mathrm{\ensuremath{\Phi}})$ is satisfied for all the pairing states and it is impossible to distinguish a chiral state from a helical one. On the other hand, a corner SQUID always gives ${I}_{c}(\mathrm{\ensuremath{\Phi}})\ensuremath{\ne}{I}_{c}(\ensuremath{-}\mathrm{\ensuremath{\Phi}})$ and ${I}_{c}(\mathrm{\ensuremath{\Phi}})={I}_{c}(\ensuremath{-}\mathrm{\ensuremath{\Phi}})$ for a chiral and a helical state, respectively. Experimental tests of these relations in corner junctions and SQUIDs may serve as a tool for unambiguously determining the pairing symmetry in ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$.
Institution: Nagoya University
Language: Latvian
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: G1179568690, G1434980962, G181688668, G2664857127, G2792699464, G3199726470, G3567532415, G3744585593, Theory of transport in Weyl semimetal, G4425055358, G4569587530, G5007900308, G5139927272, Physics of Odd-frequency pairings Theory and Experiment, G641733885, G6893310725, Theory of spin and heat transport in topological insulator/superconductor junctions, G769557534, G7912482005, PRC桁の長支間橋への応用, G909170654
OpenAlex ID: W2586728963