Enhanced superconductivity at the interface of W/Sr2RuO4 point contacts

He Wang, Weijian Lou, Jiawei Luo, Jian Wei, Y. Liu, J. E. Ortmann, Z. Q. Mao

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Differential resistance measurements are conducted for point contacts (PCs) between the Sr2RuO4 (SRO) single crystal and the tungsten tip approaching along the c axis direction of the crystal. Since the contact is made at liquid helium temperature and the tungsten tip is hard enough to penetrate through the surface layer, consistent superconducting features are observed. First, with the tip pushed towards the crystal, the zero-bias conductance peak (ZBCP) due to Andreev reflection at the normal-superconducting interface increases from 3% to more than 20%, much larger than previously reported, and extends to temperatures higher than the bulk transition temperature. Reproducible ZBCP within 0.2 mV may also help determine the gap value of SRO, on which no consensus has been reached. Second, the logarithmic background can be fitted with the Altshuler-Aronov theory of electron-electron interaction for tunneling into quasi-two-dimensional electron systems. Feasibility of such fitting confirms that spectroscopic information such as density of states is probed, and electronic temperature retrieved from such fitting can be important to analyze the PC spectra. Third, at bias much higher than 0.2 mV there are conductance dips due to the critical current effect. These dips persist up to 6.2 K, possibly due to enhanced superconductivity under uniaxial pressure.

Original languageEnglish (US)
Article number184514
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume91
Issue number18
DOIs
StatePublished - May 22 2015

Fingerprint

Point contacts
Superconductivity
Tungsten
superconductivity
Electron-electron interactions
Helium
tungsten
Crystals
Electron tunneling
Critical currents
Contacts (fluid mechanics)
Temperature
Superconducting transition temperature
liquid helium
Single crystals
crystals
critical current
surface layers
electron scattering
electrons

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

@article{14717c5cdd27418e9c119f15273c5a4b,
title = "Enhanced superconductivity at the interface of W/Sr2RuO4 point contacts",
abstract = "Differential resistance measurements are conducted for point contacts (PCs) between the Sr2RuO4 (SRO) single crystal and the tungsten tip approaching along the c axis direction of the crystal. Since the contact is made at liquid helium temperature and the tungsten tip is hard enough to penetrate through the surface layer, consistent superconducting features are observed. First, with the tip pushed towards the crystal, the zero-bias conductance peak (ZBCP) due to Andreev reflection at the normal-superconducting interface increases from 3{\%} to more than 20{\%}, much larger than previously reported, and extends to temperatures higher than the bulk transition temperature. Reproducible ZBCP within 0.2 mV may also help determine the gap value of SRO, on which no consensus has been reached. Second, the logarithmic background can be fitted with the Altshuler-Aronov theory of electron-electron interaction for tunneling into quasi-two-dimensional electron systems. Feasibility of such fitting confirms that spectroscopic information such as density of states is probed, and electronic temperature retrieved from such fitting can be important to analyze the PC spectra. Third, at bias much higher than 0.2 mV there are conductance dips due to the critical current effect. These dips persist up to 6.2 K, possibly due to enhanced superconductivity under uniaxial pressure.",
author = "He Wang and Weijian Lou and Jiawei Luo and Jian Wei and Y. Liu and Ortmann, {J. E.} and Mao, {Z. Q.}",
year = "2015",
month = "5",
day = "22",
doi = "10.1103/PhysRevB.91.184514",
language = "English (US)",
volume = "91",
journal = "Physical Review B-Condensed Matter",
issn = "1098-0121",
publisher = "American Physical Society",
number = "18",

}

Enhanced superconductivity at the interface of W/Sr2RuO4 point contacts. / Wang, He; Lou, Weijian; Luo, Jiawei; Wei, Jian; Liu, Y.; Ortmann, J. E.; Mao, Z. Q.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 91, No. 18, 184514, 22.05.2015.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Enhanced superconductivity at the interface of W/Sr2RuO4 point contacts

AU - Wang, He

AU - Lou, Weijian

AU - Luo, Jiawei

AU - Wei, Jian

AU - Liu, Y.

AU - Ortmann, J. E.

AU - Mao, Z. Q.

PY - 2015/5/22

Y1 - 2015/5/22

N2 - Differential resistance measurements are conducted for point contacts (PCs) between the Sr2RuO4 (SRO) single crystal and the tungsten tip approaching along the c axis direction of the crystal. Since the contact is made at liquid helium temperature and the tungsten tip is hard enough to penetrate through the surface layer, consistent superconducting features are observed. First, with the tip pushed towards the crystal, the zero-bias conductance peak (ZBCP) due to Andreev reflection at the normal-superconducting interface increases from 3% to more than 20%, much larger than previously reported, and extends to temperatures higher than the bulk transition temperature. Reproducible ZBCP within 0.2 mV may also help determine the gap value of SRO, on which no consensus has been reached. Second, the logarithmic background can be fitted with the Altshuler-Aronov theory of electron-electron interaction for tunneling into quasi-two-dimensional electron systems. Feasibility of such fitting confirms that spectroscopic information such as density of states is probed, and electronic temperature retrieved from such fitting can be important to analyze the PC spectra. Third, at bias much higher than 0.2 mV there are conductance dips due to the critical current effect. These dips persist up to 6.2 K, possibly due to enhanced superconductivity under uniaxial pressure.

AB - Differential resistance measurements are conducted for point contacts (PCs) between the Sr2RuO4 (SRO) single crystal and the tungsten tip approaching along the c axis direction of the crystal. Since the contact is made at liquid helium temperature and the tungsten tip is hard enough to penetrate through the surface layer, consistent superconducting features are observed. First, with the tip pushed towards the crystal, the zero-bias conductance peak (ZBCP) due to Andreev reflection at the normal-superconducting interface increases from 3% to more than 20%, much larger than previously reported, and extends to temperatures higher than the bulk transition temperature. Reproducible ZBCP within 0.2 mV may also help determine the gap value of SRO, on which no consensus has been reached. Second, the logarithmic background can be fitted with the Altshuler-Aronov theory of electron-electron interaction for tunneling into quasi-two-dimensional electron systems. Feasibility of such fitting confirms that spectroscopic information such as density of states is probed, and electronic temperature retrieved from such fitting can be important to analyze the PC spectra. Third, at bias much higher than 0.2 mV there are conductance dips due to the critical current effect. These dips persist up to 6.2 K, possibly due to enhanced superconductivity under uniaxial pressure.

UR - http://www.scopus.com/inward/record.url?scp=84930216579&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84930216579&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.91.184514

DO - 10.1103/PhysRevB.91.184514

M3 - Article

AN - SCOPUS:84930216579

VL - 91

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 18

M1 - 184514

ER -