Submicron YBaCuO biepitaxial Josephson junctions: d-wave effects and phase dynamics

Abstract

We report a systematic study of the transport properties of high critical temperature superconductor ͑HTS͒ biepitaxial Josephson junctions in the submicron range. Junction performances point to more uniform and reproducible devices and to better control of d-wave intrinsic properties. Outcomes promote novel insights into the transport mechanisms across grain boundaries and encourage further developments in the control of dissipation in HTS devices. The application of nanotechnology to HTS could be an additional tool to properly engineer the junction properties to match specific circuit design also in view of the integration into hybrid quantum circuits.

Microwave Response of SuperconductingYBa2Cu3O7−δNanowire Bridges Sustaining the Critical Depairing Current: Evidence of Josephson-li

“…The patterning of HTS films on the nano scale is an extremely challenging task. The most viable technology is the pattern transfer through a hard mask using Ar ion etching [22,23]. However, the detrimental effect of the Ar ion etching on the exposed surfaces of YBCO causes damaged layers having reduced superconducting or even insulating properties [24].…”

Resolving the effects of frequency-dependent damping and quantum phase diffusion in YBa2Cu3O7−Stornaiuolo1, Rotoli2, Massarotti3 et al. 2013Phys. Rev. BSelf Cite300300View full textAdd to dashboardCite

“…The junctions behavior can be simulated using a frequency dependent damping model. The quality factors obtained by the fits indicate a moderately damped regime [7,20,21]. Classical phase diffusion, in a frequency dependent approach, describes quite well the behavior of the devices, as far as E c << E J .…”

“…The reduction of the junctions' size allows one to minimize the influence of the GB microstructure on the transport properties of the devices, [12,19,20] while the use of LSAT substrate reduces the parasitic capacitance present in the more common SrTiO 3 (STO) based junctions. [21] Using Monte Carlo simulations, we extract the frequency dependent damping of these devices and show that, for a particular range of parameters, the quantum phase diffusion regime can be attained.…”

What happens in Josephson junctions at high critical current densities

“…4(b). A comparative study of the phase dynamics of biepitaxial JJs on STO and LSAT substrates [25][26][27]51], confirms the effects of the stray capacitance of the STO substrate [58][59][60]. These experiments [25,51] use SCD measurements for a more sophisticated estimate of the effective C and have given a more quantitative account of the effects of nonequilibrium heating mechanisms in high-J c junctions [52].…”

“…The small dimensions of these devices (width w = = 600 nm) are expected to reduce the influence of microstructural defects in the junctions properties. As a consequence, there is a good correspondence between the switching voltage V sw and the I c R n product [26,27], where R n is the normal state resistance of the junction. These curves give clear benchmarks for the low-I c limit, completing all known extensions of the RSJ model.…”