Macroscopic Quantum Tunneling in Superconducting Junctions of β-Ag₂Se Topological Insulator Nanowire

Abstract

We report on the fabrication and electrical transport properties of superconducting junctions made of β-AgSe topological insulator (TI) nanowires in contact with Al superconducting electrodes. The temperature dependence of the critical current indicates that the superconducting junction belongs to a short and diffusive junction regime. As a characteristic feature of the narrow junction, the critical current decreases monotonously with increasing magnetic field. The stochastic distribution of the switching current exhibits the macroscopic quantum tunneling behavior, which is robust up to T = 0.8 K. Our observations indicate that the TI nanowire-based Josephson junctions can be a promising building block for the development of nanohybrid superconducting quantum bits.

Hopping conductance and macroscopic quantum tunneling effect in three dimensional Pbx(SiO2)1−x nanogranular films

“…Thus the transport properties of the granular superconductor in the insulating regime need further investigation. On the other hand, the dissipation effect has been observed in the quasi one dimensional (1D) superconducting nanowires [34][35][36][37][38][39] and 2D disordered superconductors [10,17] near the SIT. Thus to check whether the dissipation effect exists in three dimensional (3D) granular superconductor is interesting and nontrivial.…”

Electrostatic control of phase slips in Ti Josephson nanotransistors

“…Phase slip events, indeed, reflect into the value of the switching current (I S ), that is, when the bias current is swept from zero to above the critical current, the bias value at which the superconductor switches to the normal state. Due to the stochastic nature of phase slip events, I S statistically spreads around I C , and its distribution [also known as the switching current probability distribution (SCPD)] naturally provides information on the phase slips dynamics of mesoscopic superconducting devices [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] under the influence of external parameters such as, for instance, the temperature or an externally applied electric field. The latter was recently investigated in hybrid graphene-based Josephson junctions [27,28], but no relationship between the electric field and the SCPDs has been observed so far in genuine all-metallic superconducting systems.…”

Flipping-Coin Experiment to Study Switching in Josephson Junctions and Superconducting Wires

“…It is common practice to measure the electrical current dependence of the switching probability (the so-called S curves) [13,14] or the switching-current distribution [15][16][17][18] for current-biased JJs and SWs. In the first case, the sample is probed with a train of N current pulses and a number of switchings n yields an estimate of the switching probability p = n/N .…”

“…There are a few phenomena that are responsible for such anticorrelation. In the moderately damped Josephson junction, as the temperature is increased, the initial broadening of the switching threshold is followed by an apparent collapse of thermal activation [13,18,20]. Such a reentrant behavior is attributed to a retrapping process that sets the phase into diffusive motion and tends to keep the junction in the metastable state (the so-called phase diffusion regime).…”