Evidence for nodal superconductivity in LaFePO

Abstract

In several iron-arsenide superconductors there is strong evidence for a fully gapped superconducting state consistent with either a conventional s-wave symmetry or an unusual $s_{\pm }$ state where there the gap changes sign between the electron and hole Fermi surface sheets. Here we report measurements of the penetration depth $\lambda (T)$ in very clean samples of the related iron-phosphide superconductor, LaFePO, at temperatures down to $\sim$ 100 mK. We find that $\lambda (T)$ varies almost perfectly linearly with $T$ strongly suggesting the presence of gap nodes in this compound. Taken together with other data, this suggests the gap function may not be generic to all pnictide superconductors.

References in corpus (20)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
• Evolution from Itinerant Antiferromagnet to Unconventional Superconductor with Fluorine Doping in La(O_{1-x}F_{x})FeAs Revealed by ^{75}As and ^{139}La Nuclear Magnetic Resonance
• ${}^{75}$As NMR studies of superconducting LaO${}_{0.9}$F${}_{0.1}$FeAs
• Microwave Penetration Depth and Quasiparticle Conductivity in PrFeAsO_1-y Single Crystals : Evidence for a Full-Gap Superconductor
• Momentum dependence of the superconducting gap in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• Meissner - London state in superconductors of rectangular cross-section in perpendicular magnetic field
• Fermi surface of superconducting LaFePO determined by quantum oscillations
• Multiple Nodeless Superconducting Gaps in (Ba0.6K0.4)Fe2As2 Superconductor from Angle-Resolved Photoemission Spectroscopy
• Field and Temperature Dependence of the Superfluid Density in LaO_{1-x}F_xFeAs Superconductors: A Muon Spin Relaxation Study
• NMR relaxation rate in superconducting pnictides: extended $s_{\pm }$ scenario
• Exponential Temperature Dependence of Penetration Depth in Single Crystal MgB_2
• Penetration depth study of superconducting gap structure of 2\textit{H}-NbSe${}_2$
• Temperature dependent anisotropy of the penetration depth and coherence length in MgB$_2
• Muon-spin rotation studies of SmFeAsO_0.85 and NdFeAsO_0.85 superconductors
• Absence of non-linear Meissner effect in YBa2Cu3O6.95

Cited by in corpus (134)

• Superconductivity in Iron Compounds
• High-temperature superconductivity in iron-based materials
• Gap symmetry and structure of Fe-based superconductors
• Pnictogen height as a possible switch between high-T_c nodeless and low-T_c nodal pairings in the iron based superconductors
• Reply to Comment on "Unconventional s-wave superconductivity in Fe(Se,Te)"
• Iron-Based Superconductors: current status of materials and pairing mechanism
• Pairing Symmetry and Pairing State in Ferropnictides: Theoretical Overview
• Unconventional Superconductivity
• Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2
• Line nodes in the energy gap of high-temperature superconducting BaFe_2(As_{1-x}P_x)_2 from penetration depth and thermal conductivity measurements
• Spin fluctuations and superconductivity in a 3D tight-binding model for BaFe2As2
• Spectroscopic scanning tunneling microscopy insights into Fe-based superconductors
• Evidence for superconducting gap nodes in the zone-centered hole bands of KFe2As2 from magnetic penetration-depth measurements
• Nodal superconducting gap structure in ferropnictide superconductor BaFe2(As0.7P0.3)2
• Pressure-induced high-Tc superconducting phase in FeSe: correlation between anion height and Tc
• Doping dependence of heat transport in the iron-arsenide superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$: from isotropic to strongly $k$-dependent gap structure
• Superfluid density of the $\pm$s-wave state for the iron-based superconductors
• ^{31}P and ^{75}As NMR evidence for a residual density of states at zero energy in superconducting BaFe_2(As_{0.67}P_{0.33})_2
• Resonant impurity scattering in the $\pm$s-gap state of the Fe-based superconductors
• Sensitivity of the superconducting state and magnetic susceptibility to key aspects of electronic structure in ferropnictides
• Momentum dependence and nodes of the superconducting gap in iron-pnictides
• Possible Multiple Gap Superconductivity with Line Nodes in Heavily Hole-Doped Superconductor KFe2As2 Studied by 75As-NQR and Specific Heat
• Evidence for Nodal Superconductivity in LaFePO from Scanning SQUID Susceptometry
• Nodeless vs nodal order parameters in LiFeAs and LiFeP superconductors
• Non-exponential London penetration depth in RFeAsO${}_{0.9}$F${}_{0.1}$ (R=La,Nd) single crystals
• Nodal gap structure of BaFe_2(As_{1-x}P_x)_2 from angle-resolved thermal conductivity in a magnetic field
• Local measurement of the penetration depth in the pnictide superconductor Ba(Fe${}_{0.95}$Co${}_{0.05}$)${}_2$As${}_2$
• Renormalization group flow, competing phases, and the structure of superconducting gap in multi-band models of Iron based superconductors
• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• Anisotropic Structure of the Order Parameter in FeSe0.45Te0.55 Revealed by Angle Resolved Specific Heat
• Band and momentum dependent electron dynamics in superconducting $\mathrm{Ba}(\mathrm{F}{\mathrm{e}}_{1-\mathrm{x}}\mathrm{C}{\mathrm{o}}_{\mathrm{x}}{)}_2\mathrm{A}{\mathrm{s}}_2$ as seen via electronic Raman scattering
• Suppression of electronic correlations by chemical pressure from FeSe to FeS
• Non-exponential London penetration depth in Ba${}_{1-}$K${}_x$Fe${}_2$As${}_2$ single crystals
• Possible three dimensional nodes in the $s\pm$ superconducting gap of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Nodes in the Gap Function of LaFePO, the Gap Function of the Fe(Se,Te) Systems, and the STM Signature of the s${}_{\pm }$ Pairing
• London penetration depth and superfluid density in single crystals of Fe(Te,Se) and Fe(Te,S) superconductors
• Topological carbon materials: a new perspective
• London penetration depth in Ba(Fe${}_{1-x}$T${}_x$)${}_2$As${}_2$ (T=Co, Ni) superconductors irradiated with heavy ions
• Orbital and spin effects for the upper critical field in As deficient disordered Fe pnictide superconductors
• Superconducting Properties of the $s^{\pm }$-wave state: Fe-based superconductors
• Contrasting Pair-Breaking Effects by Doping Mn and Zn in Ba0.5K0.5Fe2As2
• A perspective on pnictide superconductors
• London penetration depth and strong pair-breaking in iron-based superconductors
• From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba,K)Fe2As2
• Anisotropic London Penetration Depth and Superfluid Density in Single Crystals of Iron-based Pnictide Superconductors
• Spin fluctuations and unconventional pairing in KFe${}_2$As${}_2$
• Superconducting Gap Structure of LaFePO Studied by Thermal Conductivity
• Three-dimensional nodal superconducting gap in single crystals Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$
• Is Fermi-surface nesting the origin of superconductivity in iron pnictides?: A fluctuation-exchange-approximation study
• Electronic nematic states tuned by isoelectronic substitution in bulk FeSe1-xSx
• Low-Temperature and High-Energy-Resolution Laser Photoemission Spectroscopy
• Optical and Raman spectroscopy studies on Fe-based superconductors
• Direct evidence for the emergence of a pressure induced nodal superconducting gap in the iron-based superconductor Ba_0.65Rb_0.35Fe_2As_2
• Short- and long-range magnetic order in LaMnAsO
• Theory of Multiband Superconductivity in Iron Pnictides
• Anomalous Temperature Dependence of the Superfluid Density Caused by Dirty-to-Clean Crossover in FeSe${}_{0.4}$Te${}_{0.6}$ Single Crystals
• Theory of thermal conductivity in extended-$s$ state superconductors: application to ferropnictides
• Nodal Superconducting Gap in $\beta$-FeS
• Superconductivity in Multi-orbital t-J1-J2 Model and its Implications for Iron Pnictides
• Small anisotropy of the lower critical field and $s_{\pm }$-wave two-gap feature in single crystal LiFeAs
• Anisotropic vortex lattice structures in the FeSe superconductor
• Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements
• The Topological Relation Between Bulk Gap Nodes and Surface Bound States : Application to Iron-based Superconductors
• A brief review on muSR studies of unconventional Fe and Cr-based superconductors
• Anisotropic fluctuations and quasiparticle excitations in FeSe_0.5Te_0.5
• Nodeless superconductivity in the presence of spin-density wave in pnictide superconductors: The case of BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Nodal gap in iron-based superconductor CsFe${}_2$As${}_2$ probed by quasiparticle heat transport
• p-Wave Superconductivity in Iron-based Superconductors
• Fermi surface topology of LaFePO and LiFeP
• Anomalous impurity effects in the iron-based superconductor KFe${}_2$As${}_2$
• LDA+DMFT Spectral Functions and Effective Electron Mass Enhancement in Superconductor LaFePO
• Self-energy effects and electron-phonon coupling in Fe-As superconductors
• Nodal superconductivity in FeS: Evidence from quasiparticle heat transport
• Anomalous proximity effects at the interface of s and s+- superconductors
• Angle-resolved photoemission spectroscopy study on iron-based superconductors
• Nodes vs. minima in the energy gap of iron-pnictides from field-induced anisotropy
• Unusual disorder effects in superconducting LaFeAs_(1-d)O_0.9F_0.1 as revealed by NMR spectroscopy
• Superconductivity at 9K in Mo5PB2 with evidence for multiple gaps
• Nematicity from mixed S_{+-} + d_{x^2-y^2} states in iron-based superconductors
• Quantum Oscillation Studies of the Fermi Surface of LaFePO
• Investigation of the Superconducting Gap Structure in SrFe${}_2$(As${}_{0.7}$P${}_{0.3}$)${}_2$ by Magnetic Penetration Depth and Flux Flow Resistivity Analysis
• The electronic instabilities of the Iron-based superconductors: a variational Monte-Carlo study
• Vertical loop nodes in iron-based superconductors
• A weak-coupling superconductivity in the electron doped NaFe${}_{0.95}$Co${}_{0.05}$As is revealed by ARPES
• Calorimetric Evidence for Nodes in the Overdoped Ba(Fe${}_{0.9}$Co${}_{0.1}$)${}_2$As${}_2$
• Pseudogap-like phase in Ca(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ revealed by ${}^{75}$As NQR
• Multigap superconductivity in RbCa2Fe4As4F2 investigated using muSR measurements
• Magnetic penetration depth in disordered iron-based superconductors
• ${}^{75}$As NMR of Ba(Fe${}_{0.93}$Co${}_{0.07}$)${}_2$As${}_2$ in High Magnetic Field
• Evidence for line nodes in the energy gap of the overdoped Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ from low-temperature specific heat measurements
• Emergent Phases of Nodeless and Nodal Superconductivity Separated by Antiferromagnetic Order in Iron-based Superconductor (Ca4Al2O6)Fe2(As1-xPx)2: 75As- and 31P-NMR Studies
• London penetration depth measurements using tunnel diode resonators
• Doping effect of Cu and Ni impurities on the Fe-based superconductor Ba0.6K0.4Fe2As2
• Phase diagram of Josephson junction between s and s+- superconductors in dirty limit
• Spin dynamics in electron-doped pnictide superconductors
• Vortex as a probe - suggested measurement of the order parameter structure in iron-based superconductors
• Anion height as a controlling parameter for the superconductivity in iron pnictides and cuprates
• Andreev bound states in iron pnictide superconductors
• Probing the pairing symmetry in the over-doped Fe-based superconductor Ba_0.35Rb_0.65Fe_2As_2 as a function of hydrostatic pressure
• Higher-order topological semimetals and nodal superconductors with an order-two crystalline symmetry
• Disentangling superconducting and magnetic orders in NaFe_1-xNi_xAs using muon spin rotation
• New insight into the physics of iron pnictides from optical and penetration depth data
• Probing the Order Parameter of Superconducting LiFeAs using Pb/LiFeAs and Au/LiFeAs Point-Contact Spectroscopy
• Doping evolution of the superconducting gap structure in heavily hole-doped Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$: heat transport study
• Observation of the Non-linear Meissner Effect
• Low-Energy Quasiparticles Probed by Heat Transport in the Iron Based Superconductor LaFePO
• Evidence of nodal superconductivity in LaFeSiH
• Simple Real-Space Picture of Nodeless and Nodal s-wave Gap Functions in Iron Pnictide Superconductors
• Superconducting gap symmetry in BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$ superconductor
• Point contact spectroscopy in Fe-based superconductors: recent advancements and future challenges
• Generating Giant Spin Currents Using Nodal Topological Superconductors
• Evidence for Nodal superconductivity in Sr${}_2$ScFePO${}_3$
• Magneto-Transport Properties of Single Crystalline LaFeAsO
• Nodeless two-gap superconductivity in stoichiometric iron pnictide LiFeAs
• Are there nodes in LaFePO, BaFe${}_2$(AsP)${}_2$, and KFe${}_2$As${}_2$ ?
• The effect of disorder on electronic Raman scattering in the superconducting state of iron pnictides
• Multi-band superconductivity in LaFeAsO_{0.9}F_{0.1} single crystals probed by high-field vortex torque magnetometry
• A polarized neutron diffraction study of the field-induced magnetization in the normal and superconducting states of Ba(Fe1-xCox)2As2 (x=0.65)
• Theory of Mixed-State Effect on Quasiparticle Interference in Iron-based Superconductors
• Direct measurement of the temperature dependence of the magnetic penetration depth in Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$ superconductors
• Absence of large nanoscale electronic inhomogeneities in the Ba(Fe1-xCox)2As2 pnictide
• Theory of Magnetic Fluctuations in Iron Pnictides
• High-energy spin fluctuation in low-$T_{\mathrm{c}}$ iron-based superconductor LaFePO${}_{0.9}$
• Absence of strong magnetic fluctuations in the iron phosphide superconductors LaFePO and Sr2ScO3FeP
• Superconducting Gap and Symmetry in FeSe_1-x_Te_x_ Studied by Specific Heat in Magnetic Fields
• Scanning Tunneling Spectroscopy on SrFe${}_2$(As${}_{1-\mathrm{x}}$P${}_{\mathrm{x}}$)${}_2$
• Modulation of pairing symmetry with bond disorder in unconventional superconductors
• Characterization of Tunnel Diode Oscillator for Qubit Readout Applications
• First-principles-based $\pm s$-wave modelling for iron-based superconductors:Studies for specific heat and nuclear magnetic relaxation rate
• Multiband superconductivity and a deep gap minimum from the specific heat in KCa${}_2$(Fe${}_{1-x}$Ni${}_x$)${}_4$As${}_4$F${}_2$ ($x$ = 0, 0.05, 0.13)
• A Field-directional Specific Heat Study on the Gap Structure of Overdoped Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Differential conductance of point contacts between an iron-based superconductor and a normal metal
• Gap Structure of the Overdoped Iron-Pnictide Superconductor Ba(Fe${}_{0.942}$Ni${}_{0.058}$)${}_2$As${}_2$: A Low-Temperature Specific-Heat Study
• Observation of a ubiquitous three-dimensional superconducting gap function in optimally-doped Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$