A Josephson phase battery

Strambini, Elia; Iorio, Andrea; Durante, O.; Citro, Roberta; Sanz-Fernández, Cristina; Guarcello, Claudio; Tokatly, I. V.; Braggio, Alessandro; Rocci, Mirko; Ligato, Nadia; Zannier, Valentina; Sorba, L.; Bergeret, F. S.; Giazotto, Francesco

doi:10.1038/s41565-020-0712-7

Cited by 113 publications

(110 citation statements)

References 59 publications

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“…For example, the InAs wires studied in the experiments of Refs. [55][56][57][58] are in a metallic regime and are good candidates for the verification of our predictions. We denote with x the axis of the NW of length L N .…”

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confidence: 60%

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Phase-controllable nonlocal spin polarization in proximitized nanowires

et al. 2020

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We study the magnetic and superconducting proximity effects in a semiconducting nanowire (NW) attached to superconducting leads and a ferromagnetic insulator (FI). We show that a sizable equilibrium spin polarization arises in the NW due to the interplay between the superconducting correlations and the exchange field in the FI. The resulting magnetization has a nonlocal contribution that spreads in the NW over the superconducting coherence length and is opposite in sign to the local spin polarization induced by the magnetic proximity effect in the normal state. For a Josephson-junction setup, we show that the nonlocal magnetization can be controlled by the superconducting phase bias across the junction. Our findings are relevant for the implementation of Majorana bound states in state-of-the-art hybrid structures.

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confidence: 60%

“…From a material perspective, our theoretical description is based on the diffusive approach and therefore our findings can be best verified in metallic NM, as Cu, or highly doped semiconducting nanowires, as those used in Refs. [55][56][57][58]. For the FI, EuS is the best candidate.…”

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confidence: 99%

Phase-controllable nonlocal spin polarization in proximitized nanowires

et al. 2020

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“…To overcome this limitation Φ B could also be generated by a permanent dissipationless superconducting coil as well as a metallic ferromagnetic layer buried in the semiconducting substrate or by directly employing a ferromagnetic insulator as dielectric substrate [17,18]. Alternatively, a proper phase bias can be generated with an additional ferromagnetic pi-junction [19] inserted in the ring or through a phasebattery [20]. The read-out voltage is only required to probe the resistance state of the PSM.…”

Section: Resultsmentioning

confidence: 99%

Persistent Josephson Phase-Slip Memory with Topological Protection

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Strambini

Paolucci

et al. 2021

Preprint

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Superconducting computing promises enhanced computational power in both classical and quantum approaches. Yet, efficient schemes for scalable and fast superconducting memories are still missing. On the one hand, the large inductance required in magnetic flux-controlled Josephson memories impedes device miniaturization and scalability. On the other hand, schemes based on the ferromagnetic order to store information often degrades superconductivity, and limits the operation speed to the magnetization switching rate of a few GHz. Here, we overcome these limitations with a fully superconducting memory cell based on the hysteretic phase-slip transition existing in long aluminum nanowire Josephson junctions. The memory logic state is codified in the topological index of the junction providing a robust protection against stocastic phase slips and magnetic flux noise. Our direct and non-destructive read-out schemes, based on local DC or AC tunneling spectroscopy, ensure reduced dissipation (≤ 40 fW) thereby yielding a very low energy per bit read-out power consumption as low as ~ 10-24 J as estimated from the typical time response of the structure (≤ 30 ps). The memory, measured over several days, showed no evidence of information degradation up to ~1.1 K, i.e., ~85% of the critical temperature of aluminum. The ease of operation combined with remarkable performance elects the Josephson phase-slip memory as an attractive storage cell to be exploited in advanced superconducting classical logic architectures or flux qubits.

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“…Such a segment imitates the external magnetic flux and serves as a specific phase battery [73], for which Josephson π (ϕ 0 ) junctions are usually used [74]. The tunable phase battery based on the combination of the spin-orbit coupling and exchange interaction in the InAs nanowire was recently implemented in [13]. We also note that the above-considered spontaneous generation of the supercurrent is not specific to hybrid SC/FM systems with the Rashba spin-orbit coupling, but also should be relevant for a wide class of interfaces between superconductors and materials with the spin polarization and broken inversion symmetry such as topological insulators and materials with the total spin polarization.…”

Section: Spontaneous Currents In Topologically Trivial Superconductinmentioning

confidence: 99%

“…The effect of strong spin-orbit coupling on the properties of bulk superconductors without the center of inversion has been actively studied for more than two decades (see reviews [1,2]). Coupling between the spin σ and the direction of the electron momentum p results in a nontrivial helicoidal structure of electron energy bands [3,4], which is mainly responsible for the appearance of Majorana modes (exotic excitations with a half-integer spin and zero charge and coincidence of a particle and an antiparticle [5,6]), for the formation of Josephson ϕ 0 junctions with a spontaneous phase difference in the ground state [7][8][9][10][11][12][13], and for the appearance of various types of superconducting phases with a finite momentum of a Cooper pair [2], similar to Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) states [14,15].…”

Section: Introductionmentioning

confidence: 99%

Spontaneous Currents and Topologically Protected States in Superconducting Hybrid Structures with the Spin–Orbit Coupling (Brief Review)

et al. 2021

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The results of recent theoretical studies of features of superconducting states in hybrid structures whose properties are significantly determined by the spin–orbit effects have been reported. The two main phenomena appearing in such systems in the presence of additional spin splitting caused either by the Zeeman effect in a magnetic field or by the exchange field: (i) the generation of spontaneous currents and (ii) the appearance of topologically nontrivial superconducting phases. It has been shown that the spin–orbit coupling can be a key mechanism that allows implementing new inhomogeneous phase structures, in particular, the so-called “phase batteries.” The effect of geometric factors on the properties of topologically nontrivial superconducting states has been analyzed. New types of topological transitions in vortex states of Majorana wires have been proposed.

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A Josephson phase battery

Cited by 113 publications

References 59 publications

Phase-controllable nonlocal spin polarization in proximitized nanowires

Phase-controllable nonlocal spin polarization in proximitized nanowires

Persistent Josephson Phase-Slip Memory with Topological Protection

Spontaneous Currents and Topologically Protected States in Superconducting Hybrid Structures with the Spin–Orbit Coupling (Brief Review)

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