Anomalous temperature dependence of the stationary Josephson tunnel current in junctions between d-wave superconductors

Abstract

Stationary Josephson current I c between d-wave superconductors was calculated for superconductorinsulator-superconductor structures with various rotations of crystals relatively to each other and the junction plane. The directionality of tunneling was taken into account. It was demonstrated that the temperature, T, dependences of I c can become nonmonotonic for certain electrode orientations due to the T-dependent ratio between the contributions of positive and negative I c components. This model gives an explanation to the effect observed in junctions involving cuprates and is an alternative to the well-known scenario that makes allowance for Andreev-Saint-James zero-energy levels.

Improving the Josephson energy in high-Tc superconducting junctions for ultra-fast electronics

“…The asymmetric properties for the voltage polarization could be related to different T c for the bottom and top electrodes. Although in [G-3-G] the IV curve is dominated by pinholes (I p ∼I c ), the results show that the polarization suppresses the superconducting c It is important to note that for d-wave superconductors the I c (T) curves could display a non-monotonic behavior due to changes in the superconducting lobes that contribute to the tunneling [40] (not considered in our analysis). The results show that at 12 K (our lower temperature), the I c R n value is strongly affected by the barrier thickness and by the reduction in the T c of the electrodes.…”

Twisted cuprate van der Waals heterostructures with controlled Josephson coupling

“…In the twisted JJs with θ > 20°, the I c R N has a nonmonotonic temperature dependence: it increases above 40 K, before dropping close to T c . This behavior can be related to the extrinsic mechanisms active at higher temperatures and/or to the intrinsic competition between the supercurrent contributions from nodal and anti-nodal regions of the Fermi surface driven by tunnel directionality [43]. In the hightemperature regime, the tunneling becomes less coherent at the two contributions that have different magnitudes [30], resulting in a higher net I c .…”

Josephson coupling in high-Tc superconducting junctions using ultra-thin BaTiO3 barriers

“…; [39] and Δ 0 = 1.76>0 . Our analysis does not consider non-monotonic effects in the I c (T) curves usually associated with d-wave superconductors [40].…”