Superconductor to resistive state switching by multiple fluctuation events in NbTiN nanostrips

Abstract

We report on measurements of the switching current distributions on two-dimensional superconducting NbTiN strips that are 5 nm thick and 80 nm wide. We observe that the width of the switching current distributions has a non-monotonous temperature dependence, where it is constant at the lowest temperatures up to about 1.5 K, after which it increases with temperature until 2.2 K. Above 2.5 K any increase in temperature decreases the distribution width which at 4.0 K is smaller than half the width observed at 0.3 K. By using a careful analysis of the higher order moments of the switching distribution, we show that this temperature dependence is caused by switching due to multiple fluctuations. We also find that the onset of switching by multiple events causes the current dependence of the switching rate to develop a characteristic deviation from a pure exponential increase, that becomes more pronounced at higher temperatures, due to the inclusion of higher order terms.

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.…”

Gate Control of Superconductivity in Mesoscopic All-Metallic Devices

“…First, the different phase slip regimes were identified thanks to the evolution of distribution standard deviation as a function of T . The Figure 7 insets show the expected behavior of the vs. T curve in the three different phase slips regimes, which is flat at low temperatures in the Quantum Phase Slip (QPS) regime [ 50 , 51 , 52 ], linear as a function of the temperature T in the Thermal Activated Phase Slip (TAPS) regime [ 53 ], and decreasing for the Multiple Phase Slip (MPS) regime as T increases [ 45 , 46 , 47 , 49 , 54 , 55 , 56 , 57 ]. The temperature , separating the QPS and the TAPS regime, occurs at about mK, while the crossover between TAPS and MPS regimes appears for mK.…”

Phase slips dynamics in gated Ti and V all-metallic supercurrent nano-transistors: a review

“…• for higher temperatures, T > T M , the phase slips events occur more than one at once, and the system shows the multiple phase slip (MPS) regime [31]. In contrast to QPS and TAPS, there are no analytical models for MPS.…”