Phase Signature of Topological Transition in Josephson Junctions

Dartiailh, Matthieu; Mayer, William; Yuan, Joseph; Wickramasinghe, Kaushini; Matos-Abiague, Alex; Žutić, Igor; Shabani, Javad

doi:10.1103/physrevlett.126.036802

Cited by 102 publications

(86 citation statements)

References 43 publications

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“…Ke et al observed an expected minimum of critical current at a gate-voltage dependent value of B [12]. Dartiailh et al reported a similar signature and additionally detected a π phase shift of the current-phase relation associated with revival of the supercurrent [10].…”

mentioning

confidence: 87%

“…Theoretically, the N region under these conditions acts as a quasi-one-dimensional topological wire bounded by trivial superconducting walls, with Majorana zero modes at its ends [1][2][3]. Compared to alternative nanowire platforms [4][5][6][7][8], planar JJs have a new experimental knob, the phase difference between bounding trivial superconductors, which can lower the magnetic field required to observe a topological phase transition, as reported in recent experiments in Al/InAs [9,10], Al/HgTe [11] and NbTiN/InSb [12].…”

mentioning

confidence: 94%

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Signatures of a topological phase transition in a planar Josephson junction

Banerjee¹,

Lesser²,

Rahman³

et al. 2022

Preprint

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A growing body of work suggests that planar Josephson junctions fabricated using superconducting hybrid materials provide a highly controllable route toward one-dimensional topological superconductivity. Among the experimental controls are in-plane magnetic field, phase difference across the junction, and carrier density set by electrostatic gate voltages. Here, we investigate planar Josephson junctions with an improved design based on an epitaxial InAs/Al heterostructure, embedded in a superconducting loop, probed with integrated quantum point contacts (QPCs) at both ends of the junction. For particular ranges of in-plane field and gate voltages, a closing and reopening of the superconducting gap is observed, along with a zero-bias conductance peak (ZBCP) that appears upon reopening of the gap. Consistency with a simple theoretical model supports the interpretation of a topological phase transition. While gap closings and reopenings generally occurred together at the two ends of the junction, the height, shape, and even presence of ZBCPs typically differed between the ends, presumably due to disorder and variation of couplings to local probes.

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mentioning

confidence: 87%

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confidence: 94%

Signatures of a topological phase transition in a planar Josephson junction

Banerjee¹,

Lesser²,

Rahman³

et al. 2022

Preprint

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“…Previous investigations 37,39,42 have shown the im- portance of properly tuning the chemical potential, magnetic field strength, and superconducting phase difference for driving the JJ into the TS state. However, the strong dependence of the TS state and the ground-state phase on the spin-orbit angle (θ so ), the magnetic field orientation (ϕ B ), and the supercurrent direction (θ c ), shown in Fig.…”

Section: B Effects Of Crystalline Anisotropymentioning

confidence: 99%

“…The interrelation between the Zeeman interaction and the Rashba SOC emerging from the lack of structure inversion symmetry 62 The x and ŷ axes define the coordinate system in the junction reference frame. The Rashba SOC strength can be controlled by using a gate on the top of the normal region 42,65 . (b) ϕB and θc characterize the orientation of the in-plane magnetic field (B) and the junction reference frame, respectively, with respect to the semiconductor [100] crystallographic axis.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic topological superconductivity in Josephson junctions

Pekerten,

Pakizer,

Hawn

et al. 2021

Preprint

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We investigate the effects of magnetic and crystalline anisotropies on the topological superconducting state of planar Josephson junctions (JJs). In junctions where only Rashba spin-orbit coupling (SOC) is present, the topological phase diagram is insensitive to the supercurrent direction, but exhibits a strong dependence on the magnetic field orientation. However, when both Rashba and Dresselhaus SOCs coexist, the topological phase diagram strongly depends on both the magnetic field and junction crystallographic orientations. We examine the impact of the magnetic and crystalline anisotropy on the current-phase relation (CPR), energy spectrum, and topological gap of phase-biased JJs, where the junction is connected in a loop and the superconducting phase difference is fixed by a loop-threading magnetic flux. The anisotropic CPR can be used to extract the ground-sate phase (i.e. the superconducting phase difference that minimizes the system free energy) behavior in phase-unbiased JJs with no magnetic flux. Under appropriate conditions, phase-unbiased JJs can self-tune into or out of the topological superconducting state by rotating the in-plane magnetic field. The magnetic field orientations at which topological transitions occur strongly depends on both the junction crystallographic orientation and the relative strength between Rashba and Dresselhaus SOCs. We find that for an optimal practical application, in which the junction exhibits topological superconductivity with a sizeable topological gap, a careful balancing of the magnetic field direction, the junction crystallographic orientation, and the relative strengths of the Rashba and Dresselhaus SOCs is required. We discuss the considerations that must be undertaken to achieve this balancing for various junction types and parameters.

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“…The anomalous phase shift could cause spin-galvanic effect, also known as inverse Edelstein effect [10,11]. Such a magneto-electric effect might be useful in future superconducting electronics and spintronics [12], such as to drive quantum phase batteries [13], to form superconducting quantum memories [14,15], or to induce topological superconductivity [16][17][18][19], etc.…”

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confidence: 99%

Anomalous Josephson Effect in Topological Insulator-Based Josephson Trijunction

Zhang,

Lyu,

Yang

et al. 2021

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We studied anomalous Josephson effect (AJE) in Josephson trijunctions fabricated on Bi2Se3, and found that the AJE in T-shaped trijunctions significantly alters the Majorana phase diagram of the trijunctions, when an in-plane magnetic field is applied parallel to two of the three single junctions. Such a phenomenon in topological insulator-based Josephson trijunction provides unambiguous evidence for the existence of AJE in the system, and might provide an additional knob for controlling the Majorana bound states in the Fu-Kane scheme of topological quantum computation.

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Phase Signature of Topological Transition in Josephson Junctions

Cited by 102 publications

References 43 publications

Signatures of a topological phase transition in a planar Josephson junction

Signatures of a topological phase transition in a planar Josephson junction

Anisotropic topological superconductivity in Josephson junctions

Anomalous Josephson Effect in Topological Insulator-Based Josephson Trijunction

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