Observation of quasiparticle Andreev bound states using<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">YBa</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn

Wang, Wan; Yamazaki, Masashi; Lee, Kiejin; Iguchi, Ienari

doi:10.1103/physrevb.60.4272

Cited by 79 publications

(47 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A wide range of features were observed, including zero bias peak structures, mostly inside gaps [11,13,24], as well as V-shaped [25,26] and U-shaped gaps [18,27]. The zero bias conductance peak may result from nano-faceting or roughness of the measured surface, as has been demonstrated by various groups [14,21,28,29].…”

mentioning

confidence: 89%

Scanning tunneling spectroscopy of a -axis YBa ₂ Cu ₃ O _{7 − δ} films: k -selectivity and the shape of the superconductor gap

Sharoni¹,

Leibovitch²,

Kohen³

et al. 2003

Europhys. Lett.

View full text Add to dashboard Cite

Abstract. -Tunneling spectroscopy of epitaxial (100) oriented YBa2Cu3O 7−δ films was performed using an STM at 4.2 K. On atomically smooth areas, tunneling spectra revealing clear U-shaped gaps with relatively low zero bias conductance were measured. These spectra can be well fitted to the tunneling theory into a d-wave superconductor only when introducing a strong dependence of the tunneling probability on the wave-vector k. Possible origins for this k -selectivity in STM measurements will be discussed. On other areas, V-shaped gaps as well as zero bias conductance peaks are observed, indicating relaxation of k -selectivity and the effect of nanofaceting, respectively.The d -wave symmetry of the order parameter of YBa 2 Cu 3 O 7−δ (YBCO) [1, 2, 3] has a special signature in the tunneling spectra measured for these superconductors. The hallmark of this is the zero bias conductance peak (ZBCP) that appears when tunneling along or near the nodal direction ([110] for YBCO). This reflects the existence of Andreev bound states at the Fermi level residing on the pair-breaking (110) surface [4,5,6,7,8]. The ZBCP was measured by numerous groups, using both macroscopic and microscopic (STM) tunnel junctions [9,10,11,12,13,14,15]. Manifestation of the d -wave order parameter in the tunneling spectra acquired along the anti-nodal ([100] for YBCO) and the c-axis directions is more controversial. The theory of tunneling into a d -wave superconductor predicts a V-shaped gap structure for both tunneling directions in the case where the density of states (DOS) is isotropically averaged over the Fermi surface [6,7]. Here, quasi-particle excitations are observed at any finite energy, since the nodal directions in k -space are monitored, resulting in a linear dependence of the dI/dV vs. V tunneling spectra on energy around the Fermi energy (zero bias). Such isotropic tunneling scenario is believed to apply to STM measurements [16]. In contrast, U-shaped gaps are predicted to appear when k -vectors along the anti-nodal direction are preferentially monitored in the tunneling process [7,11,14,17,18]. Resolving this issue is thus important for

show abstract

mentioning

confidence: 89%

Scanning tunneling spectroscopy of a -axis YBa ₂ Cu ₃ O _{7 − δ} films: k -selectivity and the shape of the superconductor gap

Sharoni¹,

Leibovitch²,

Kohen³

et al. 2003

Europhys. Lett.

View full text Add to dashboard Cite

show abstract

“…3,4,5,6,7,8,9,10 The ZES is also responsible for the low-temperature anomaly of the Josephson current between the two unconventional superconductors. 11,12,13,14,15,16,17,18,19,20,21 An electron incident into a normal-metal / superconductor (NS) interface suffers the Andreev reflection 22 by the pair potential in the superconductor.…”

Section: Introductionmentioning

confidence: 99%

Split of zero-bias conductance peak in normal-metal/d-wave superconductor junctions

2004

View full text Add to dashboard Cite

Effects of impurity scatterings on the conductance in normal-metal / d wave superconductor junctions are discussed by using the single-site approximation. So far, the split of the zero-bias conductance peak has been believed to be an evidence of the broken time reversal symmetry states at the surface of high-Tc superconductors. In this paper, however, it is shown that the impurity scattering near the interface also causes the split of the zero-bias conductance peak. Typical conductance spectra observed in experiments at finite temperatures and under external magnetic fields are explained well by the present theory.

show abstract

“…Tunneling spectra depend strongly on this symmetry and therefore tunneling spectroscopy is a very sensitive probe for its study. In a d-symmetry and (110) orientation, for instance, the differential conductance has a peak at zero voltage, called zero-bias conductance peak (ZBCP) which has been predicted theoretically by differents works [3,4,5,6,7,8] and observed experimentally [9,10,11,12,13,14] . The existence of the ZBCP is due to the formation of Andreev bound states at the Fermi level (zero energy states) near to the interface [15,16,17].…”

Section: Introductionmentioning

confidence: 96%

Quantum point contact conductance in normal-metal/insulator/metal/superconductor junctions

2005

View full text Add to dashboard Cite

The effect of an insulating barrier located at a distance a from a NS quantum point contact is analyzed in this work. The Bogoliubov de Gennes equations are solved for NINS junctions (S: anysotropic superconductor, I: insulator and N: normal metal), where the NIN region is a quantum wire. For a = 0, bound states and resonances in the differential conductance are predicted. These resonances depend on the symmetry of the pair potential, the strength of the insulating barrier and a. Our results show that in a NINS quantum point contact the number of resonances vary with the symmetry of the order parameter. This is to be contrasted with the results for the NINS junction, in which only the position of the resonances changes with the symmetry.

show abstract

Observation of quasiparticle Andreev bound states usingYBa2Cu3O

Cited by 79 publications

References 29 publications

Scanning tunneling spectroscopy of a -axis YBa ₂ Cu ₃ O _{7 − δ} films: k -selectivity and the shape of the superconductor gap

Scanning tunneling spectroscopy of a -axis YBa ₂ Cu ₃ O _{7 − δ} films: k -selectivity and the shape of the superconductor gap

Split of zero-bias conductance peak in normal-metal/d-wave superconductor junctions

Quantum point contact conductance in normal-metal/insulator/metal/superconductor junctions

Contact Info

Product

Resources

About

Observation of quasiparticle Andreev bound states usingYBa2Cu3O

Cited by 79 publications

References 29 publications

Scanning tunneling spectroscopy of a -axis YBa 2 Cu 3 O 7 − δ films: k -selectivity and the shape of the superconductor gap

Scanning tunneling spectroscopy of a -axis YBa 2 Cu 3 O 7 − δ films: k -selectivity and the shape of the superconductor gap

Split of zero-bias conductance peak in normal-metal/d-wave superconductor junctions

Quantum point contact conductance in normal-metal/insulator/metal/superconductor junctions

Contact Info

Product

Resources

About

Scanning tunneling spectroscopy of a -axis YBa ₂ Cu ₃ O _{7 − δ} films: k -selectivity and the shape of the superconductor gap

Scanning tunneling spectroscopy of a -axis YBa ₂ Cu ₃ O _{7 − δ} films: k -selectivity and the shape of the superconductor gap