Role of critical current on the point-contact Andreev reflection spectra between a normal metal and a superconductor

Sheet, Goutam; Mukhopadhyay, Sourin; Raychaudhuri, Pratap

doi:10.1103/physrevb.69.134507

Cited by 199 publications

(213 citation statements)

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“…9, accompanied by the s-wave BTK fitting curves denoted by the red solid lines. Because the spectra were affected by the critical current effect at higher temperature near T c [36], it is difficult to determine the background for these temperatures. Therefore, these results have not been included in our theoretical analysis.…”

Section: B Theoretical Model -S-wave Btk Theorymentioning

confidence: 99%

Distinct pairing symmetries inNd1.85Ce0.15CuO4−yandLa1.89

et al. 2005

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We used point-contact tunnelling spectroscopy to study the superconducting pairing symmetry of electron-doped N d1.85Ce0.15CuO4−y (NCCO) and hole-doped La1.89Sr0.11CuO4 (LSCO). Nearly identical spectra without zero bias conductance peak (ZBCP) were obtained on the (110) and (100) oriented surfaces (the so-called nodal and anti-nodal directions) of NCCO. In contrast, LSCO showed a remarkable ZBCP in the nodal direction as expected from a d-wave superconductor. Detailed analysis reveals an s-wave component in the pairing symmetry of the NCCO sample with ∆/kBTc = 1.66, a value remarkable close to that of a weakly coupled BCS superconductor. We argue that this s-wave component is formed at the Fermi surface pockets centered at (±π,0) and (0,±π) although a d-wave component may also exist.

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Section: B Theoretical Model -S-wave Btk Theorymentioning

confidence: 99%

Distinct pairing symmetries inNd1.85Ce0.15CuO4−yandLa1.89

et al. 2005

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“…Two sharp peaks symmetric about V = 0 in dV /dI vs. V plots obtained from thermal limit point-contacts is a signature of superconductivity in the point-contacts [16,17].…”

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confidence: 99%

“…However, when the contact diameter is large (thermal regime), R M contributes most to the total contact resistance. Therefore resistive transitions lead to non-linearities in the I − V characteristics of point-contacts in the thermal regime [16]. No spectroscopy can be performed in the thermal regime due to the permitted inelastic processes at the interface.…”

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confidence: 99%

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Unconventional superconductivity at mesoscopic point contacts on the 3D Dirac semimetal Cd3As2

et al. 2015

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Since the three dimensional (3D) Dirac semi-metal Cd 3 As 2 exists close to topological phase boundaries, in principle it should be possible to drive it into exotic new phases, like topological superconductors, by breaking certain symmetries. Here we show that the mesoscopic point-contacts between silver (Ag) and Cd 3 As 2 exhibit superconductivity up to a critical temperature (onset) of 6 K while neither Cd 3 As 2 nor Ag are superconductors. A gap amplitude of 6.5 meV is measured spectroscopically in this phase that varies weakly with temperature and survives up to a remarkably high temperature of 13 K indicating the presence of a robust normal-state pseudogap. The observations indicate the emergence of a new unconventional superconducting phase that exists only in a quantum mechanically confined region under a point-contact between a Dirac semi-metal and a normal metal. * These authors contributed equally to the work † ashok@chemistry.iitd.ac.in ‡ goutam@iisermohali.ac.in 1 arXiv:1410.2072v1 [cond-mat.supr-con]

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“…The data for the Ni 19 Pd 81 film is shown in figure 2(f). The high bias dips on the spectra have been associated with the critical current being exceeded in the contact region 27 . In order to fit the data, the spectra for the single crystal were normalized to the conductance spectra obtained using a nonsuperconducting Pt tip, as shown in Fig.…”

Section: Figurementioning

confidence: 99%

Evidence for spin mixing in holmium thin film and crystal samples

et al. 2011

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In a number of recent experiments, holmium has been shown to promote spin triplet pairing when in proximity to a spin singlet superconductor. The condition for the support of spin triplet pairing is that the ferromagnet should have an inhomogeneous magnetic state at the interface with the superconductor. Here we use Andreev reflection spectroscopy to study the properties of single ferromagnet/superconductor interfaces formed of holmium and niobium, as a function of the contact resistance of the junction between them. We find that both single crystal and c-axis oriented thin film holmium show unusual behavior for low junction contact resistance, characteristic of spin mixing type properties, which are thought necessary to underpin spin triplet formation. We also explore whether this signature is observed when the junction is formed of Ni 19 Pd 81 and niobium.

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Role of critical current on the point-contact Andreev reflection spectra between a normal metal and a superconductor

Cited by 199 publications

References 26 publications

Distinct pairing symmetries inNd1.85Ce0.15CuO4−yandLa1.89

Distinct pairing symmetries inNd1.85Ce0.15CuO4−yandLa1.89

Unconventional superconductivity at mesoscopic point contacts on the 3D Dirac semimetal Cd3As2

Evidence for spin mixing in holmium thin film and crystal samples

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