A theoretical study of the current-phase relation in Josephson contacts

Haberkorn, W.; Knauer, H.; Richter, Jessica

doi:10.1002/pssa.2210470266

Cited by 77 publications

(64 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consequently, when eV ≤ √ R∆, 9 the Josephson current through the SIS junction is nearly the same as without the probe, i.e. we recover the standard Ambegaokar-Baratoff result 9,[19][20][21][22][23][24][25] , as shown in Fig. 2(b).…”

Section: Short Josephson Junctionsupporting

confidence: 74%

Andreev-level spectroscopy and Josephson-current switching in a three-terminal Josephson junction

1998

View full text Add to dashboard Cite

We calculate the electrical currents through a superconductor -insulator -superconductor junction which is also weakly coupled to a normal metal side probe. The voltage V applied to the normal metal terminal controls the occupation of Andreev energy levels En, and therefore controls the Josephson current flowing through these levels. Whenever the probe voltage crosses an Andreev level, the Josephson current changes abruptly by an amount equal to the current flowing through the Andreev level. The differential conductance along the normal metal terminal permits spectroscopy of the Andreev levels. In a short junction (L ≪ ξ0), the critical current switches abruptly from the Ambegaokar-Baratoff value to zero when the probe voltage is approximately equal to the superconducting energy gap (|eV | ≃ ∆). The magnitude of the Josephson current switching in a long junction (L ≫ ξ0) , and the range of probe voltages over which the Josephson current differs from its equilibrium value, are much smaller than for three-terminal ballistic superconductor -normal metal -superconductor junctions.

show abstract

Section: Short Josephson Junctionsupporting

confidence: 74%

Andreev-level spectroscopy and Josephson-current switching in a three-terminal Josephson junction

1998

View full text Add to dashboard Cite

show abstract

“…Firstly, we should have a sinusoidal current-phase dependency, which is in accordance with the transmission value and temperature in our experiment [18]. Secondly, the Andreev levels, that carry supercurrent in the junction, may only weakly deviate from the longitudinal propagation.…”

supporting

confidence: 52%

h/e Superconducting Quantum Interference through Trivial Edge States in InAs

et al. 2018

View full text Add to dashboard Cite

Josephson junctions defined in strong spin orbit semiconductors are highly interesting for the search for topological systems. However, next to topological edge states that emerge in a sufficient magnetic field, trivial edge states can also occur. We study the trivial edge states with superconducting quantum interference measurements on non-topological InAs Josephson junctions. We observe a SQUID pattern, an indication of superconducting edge transport. Also, a remarkable h/e SQUID signal is observed that, as we find, stems from crossed Andreev states.Topological systems are a hot topic in condensed matter physics [1]. This is largely motivated by the existence of states at the interface between two topologically distinct phases, for example helical edge states in a quantum spin Hall insulator (QSHI) [2, 3]. Inducing superconductivity in these edge states would form a topological superconductor [1]. Superconducting edge transport has already been found in materials that are predicted to be QSHI [4, 5]. However, edge states can also have a non-topological origin. Trivial edge conduction is found in InAs alongside the chiral edge states in the QH regime [6] and recently in the proposed QSHI InAs/GaSb as well [7,8]. To be able to discriminate between topological and trivial states it is crucial to study transport through trivial edges also and clarify differences and similarities between them. In this work we study the superconducting transport through trivial edge states in non-topological InAs Josephson junctions using superconducting quantum interference (SQI) measurements. We find supercurrent carried by these edge states and an intriguing h/e periodic signal in a superconducting quantum interference device (SQUID) geometry.Trivial edge states arise when the Fermi level resides in the band gap in the bulk, while being pinned in the conduction band at the surface.Then, band bending leads to electron accumulation at that surface as schematically drawn in Fig. 1(a). The Fermi level pinning can have several origins: truncating the Bloch functions in space [9,10], a work function difference [11], the built-in electric field in a heterostack [12] and the surface termination [13]. In our 2D InAs Josephson junctions the accumulation surface is located at the edge of the mesa that is defined by wet etching. The quantum well is MBE grown on a GaSb substrate serving as a global bottom gate [14]. The superconducting electrodes are made of sputtered NbTiN with a spacing of 500 nm and a width of 4 µm. A SiN x dielectric separates the top gate from the heterostructure. Electrical quasi-four terminal measurements [see Fig.1(b)] are performed in a dilution refrigerator with an electron temperature of 60 mK unless stated otherwise.The electron density in the InAs quantum well is altered by using the electrostatic gates, V tg and V bg , located above and below the 2DEG. Decreasing the density subsequently increases the normal state resistance R n and reduces the switching current I s as shown in Fig. 2(a). A full resistance map ...

show abstract

“…for arbitrary disorder potential. It is the multi-channel generalization of a formula first obtained by Haberkorn et al [24] (and subsequently rederived by several authors [25]- [27]) for the single-channel case (appropriate for a geometry such as a planar tunnel barrier, where the different scattering channels are uncoupled). A formula of similar generality for the conductance is the multi-channel Landauer formula [23,28] …”

mentioning

confidence: 96%

Three “Universal” Mesoscopic Josephson Effects

Beenakker

1992

Springer Series in Solid-State Sciences

View full text Add to dashboard Cite

Abstract. A recent theory is reviewed for the sample-to-sample fluctuations in the critical current of a Josephson junction consisting of a disordered point contact or microbridge. The theory is based on a relation between the supercurrent and the scattering matrix in the normal state. The root-mean-square amplitude rms I c of the critical current I c at zero temperature is given by rms I c ≃ e∆ 0 /h, up to a numerical coefficient of order unity (∆ 0 is the energy gap). This is the superconducting analogue of "Universal Conductance Fluctuations" in the normal state. The theory can also be applied to a ballistic point contact, where it yields the analogue of the quantized conductance, and to a quantum dot, where it describes supercurrent resonances. All three phenomena provide a measurement of the supercurrent unit e∆ 0 /h, and are "universal" through the absence of a dependence on junction parameters.

show abstract

A theoretical study of the current-phase relation in Josephson contacts

Cited by 77 publications

References 8 publications

Andreev-level spectroscopy and Josephson-current switching in a three-terminal Josephson junction

Andreev-level spectroscopy and Josephson-current switching in a three-terminal Josephson junction

h/e Superconducting Quantum Interference through Trivial Edge States in InAs

Three “Universal” Mesoscopic Josephson Effects

Contact Info

Product

Resources

About