scholarly journals Theory of point contact spectroscopy in correlated materials

2015 ◽  
Vol 112 (3) ◽  
pp. 651-656 ◽  
Author(s):  
Wei-Cheng Lee ◽  
Wan Kyu Park ◽  
Hamood Z. Arham ◽  
Laura H. Greene ◽  
Philip Phillips
Keyword(s):  
Scattering Length ◽  
Point Contact ◽  
Microscopic Theory ◽  
Effective Density ◽  
Strongly Correlated ◽  
Metallic Electrode ◽  
Zero Bias ◽  
Point Contact Spectroscopy ◽  
Conductance Peak ◽  
Zero Bias Conductance

We developed a microscopic theory for the point-contact conductance between a metallic electrode and a strongly correlated material using the nonequilibrium Schwinger-Kadanoff-Baym-Keldysh formalism. We explicitly show that, in the classical limit, contact size shorter than the scattering length of the system, the microscopic model can be reduced to an effective model with transfer matrix elements that conserve in-plane momentum. We found that the conductance dI/dV is proportional to the effective density of states, that is, the integrated single-particle spectral function A(ω = eV) over the whole Brillouin zone. From this conclusion, we are able to establish the conditions under which a non-Fermi liquid metal exhibits a zero-bias peak in the conductance. This finding is discussed in the context of recent point-contact spectroscopy on the iron pnictides and chalcogenides, which has exhibited a zero-bias conductance peak.

scholarly journals POINT CONTACT STUDY OF THE SUPERCONDUCTING ORDER PARAMETER IN RuSr2GdCu2O8

2005 ◽  
Vol 19 (01n03) ◽  
pp. 323-325 ◽  
Author(s):  
S. PIANO ◽  
F. BOBBA ◽  
F. GIUBILEO ◽  
A. M. CUCOLO ◽  
A. VECCHIONE
Keyword(s):  
Order Parameter ◽  
Magnetic Order ◽  
Point Contact ◽  
Superconducting Order Parameter ◽  
Zero Bias ◽  
Bulk Superconductivity ◽  
Conductance Peak ◽  
Wave Symmetry ◽  
Zero Bias Conductance ◽  
D Wave

We have performed a detailed study of the conductance characteristics obtained by point contact junctions realized between a normal Pt / Ir tip and syntered RuSr 2 GdCu 2 O 8 ( Ru -1212) samples. Indeed, this compound is subject of great interest due to the coexistence of both magnetic order and bulk superconductivity. In our experiments, the low temperature tunneling spectra reproducibly show a zero bias conductance peak that can be well reproduced by a generalized BTK model in the case of d-wave symmetry of the superconducting order parameter.

scholarly journals Anomalous Zero-Bias Conductance Peak in a Nb–InSb Nanowire–Nb Hybrid Device

Nano Letters ◽  
2012 ◽  
Vol 12 (12) ◽  
pp. 6414-6419 ◽  
Author(s):  
M. T. Deng ◽  
C. L. Yu ◽  
G. Y. Huang ◽  
M. Larsson ◽  
P. Caroff ◽  
...  
Keyword(s):  
Zero Bias ◽  
Hybrid Device ◽  
Conductance Peak ◽  
Zero Bias Conductance

On the Origin of Zero-Bias Conductance Peak in High-Tc Superconductors

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3027-3030
Author(s):  
Alexander B. Nazarenko ◽  
Ernst A. Pashitskii ◽  
Alexander E. Pashitskii
Keyword(s):  
Elastic Scattering ◽  
Order Parameter ◽  
Magnetic Impurities ◽  
High Tc Superconductors ◽  
Zero Bias ◽  
High Tc ◽  
Conductance Peak ◽  
Wave Symmetry ◽  
Zero Bias Conductance ◽  
D Wave

We show that the zero-bias conductance peak observed in tunnel and point junctions of cuprates can be a consequence of "unitary" elastic scattering of the carriers by non-magnetic impurities in the vicinity of the junction interface and d-wave symmetry of the order parameter.

scholarly journals Zero-bias conductance peak and Josephson effect in graphene-NbTiN junctions

2012 ◽  
Vol 85 (20) ◽  
Author(s):  
M. Popinciuc ◽  
V. E. Calado ◽  
X. L. Liu ◽  
A. R. Akhmerov ◽  
T. M. Klapwijk ◽  
...  
Keyword(s):  
Josephson Effect ◽  
Zero Bias ◽  
Conductance Peak ◽  
Zero Bias Conductance

POINT CONTACT SPECTROSCOPY IN ORIENTED YBa2Cu3O7−δ

1993 ◽  
Vol 07 (01n03) ◽  
pp. 127-130
Author(s):  
NIR HASS ◽  
D. ILZYCER ◽  
G. DEUTSCHER ◽  
G. DESGARDIN ◽  
I. MONOT ◽  
...  
Keyword(s):  
High Temperature Superconductors ◽  
Point Contact ◽  
Theoretical Explanation ◽  
Precise Determination ◽  
Fermi Velocity ◽  
Zero Bias ◽  
Point Contact Spectroscopy ◽  
Out Of Plane ◽  
Plane Direction

We report point contact spectroscopy measurements on YBa 2 Cu 3 O 7−δ thin films and textured bulk ceramics. The I(V) curves measured along the Copper-Oxygen (ab) plane direction are characteristic of the Andreev reflection phenomenon, with a sharp break at the gap edge. This allows a rather precise determination of the (in plane) gap, Δ = 20 mev . Subgap structure suggests the existence of a smaller gap for some orientations in the (ab) plane, of the order of 12 mev. The data also enabled us to set a lower bound to the inplane Fermi velocity in YBa 2 Cu 3 O 7−δ: v F ≥ 7 × 107 cm/sec . The value of v F has a crucial importance in the determination of the theoretical explanation for superconductivity in the High Temperature Superconductors. For out of plane measurements, only a weak zero bias anomaly is observed at energies up to 5 mev.

Influence of the Impurity-scattering on Zero-bias Conductance Peak in Ferromagnet/Insulator/d-wave Superconductor Junctions

2003 ◽  
Vol 72 (4) ◽  
pp. 895-899 ◽  
Author(s):  
Nobukatsu Yoshida ◽  
Yasuhiro Asano ◽  
Hiroyoshi Itoh ◽  
Yukio Tanaka ◽  
Jun-ichiro Inoue ◽  
...  
Keyword(s):  
Impurity Scattering ◽  
Zero Bias ◽  
Conductance Peak ◽  
Zero Bias Conductance ◽  
D Wave
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