Tunneling between noncentrosymmetric superconductors with significant spin-orbit splitting studied theoretically within a two-band treatment

Tunneling between noncentrosymmetric superconductors with significant spin-orbit splitting is studied theoretically in a two-band treatment of the problem. We find that the critical Josephson current may be modulated by changing the relative angle between the vectors describing absence of inversion symmetry on each side of the junction. The presence of two gaps also results in multiple steps in the quasiparticle current-voltage characteristics. We argue that both these effects may help to determine the pairing states in materials like ${\mathrm{CePt}}_3\mathrm{Si}$, $\mathrm{UIr}$, and ${\mathrm{Cd}}_2{\mathrm{Re}}_2{\mathrm{O}}_7$. We propose experimental tests of these ideas, including scanning tunneling microscopy.

Figure 1

(Color online) The quasiparticle current-voltage diagram at $T=0$ for angles $\zeta =0,\pi ∕2,\pi$, $x=0.7$, and $d=1$. The graphs are displaced in the vertical direction for clarity. Left-hand panel, $\mid {\chi }_{-}\mid ∕\mid {\chi }_{+}\mid =0.5$. Right-hand panel, $\mid {\chi }_{-}\mid ∕\mid {\chi }_{+}\mid =0.01$.