Bogoliubov Quasiparticle on the Gossamer Fermi Surface in Electron-Doped Cuprates

Abstract

In contrast to hole-doped cuprates, electron-doped cuprates consistently exhibit strong antiferromagnetic correlations with a commensurate (π, π) ordering wave vector, leading to the prevalent belief that antiferromagnetic spin fluctuations mediate Cooper pairing in these unconventional superconductors. However, early investigations produced two paradoxical findings: while antiferromagnetic spin fluctuations create the largest pseudogap at "hot spots" in momentum space, Raman scattering and angle-resolved photoemission spectroscopy measurements using the leading-edge method seem to suggest the superconducting gap is also maximized at these locations. This presented a dilemma for spin-fluctuation-mediated pairing: Cooper pairing is strongest at momenta where normal state low energy spectral weight is most suppressed. Here we investigate this dilemma in Nd2-xCexCuO4 using angle-resolved photoemission spectroscopy under significantly improved experimental conditions. The unprecedented signal-to-noise ratio and resolution allow us to directly observe the Bogoliubov quasiparticles, demonstrating the existence and importance of two sectors of states: 1. The reconstructed main band and the states gapped by the antiferromagnetic pseudogap around the hot spots. 2. The gossamer Fermi surface states with distinct dispersion inside the pseudogap, from which Bogoliubov quasiparticle coherence peaks emerge below Tc. Supported by numerical results, we propose that the non-zero modulus of the antiferromagnetic order parameter causes the former, while fluctuations in the antiferromagnetic order parameter orientation are responsible for the latter. Our revelations of the gossamer Fermi surface reconcile the paradoxical observations, deepening our understanding of superconductivity in electron-doped cuprates in particular, and unconventional superconductivity in general.

Submitted version 30 pages, 4 main figures, 8 extended data figures. Accepted version in press at Nature Physics

References in corpus (7)

• Theory of Intertwined Orders in High Temperature Superconductors
• Electronic liquid crystal state in the high-temperature superconductor YBCO(6.45)
• Spin correlations in the electron-doped high-transition-temperature superconductor Nd{2-x}Ce{x}CuO{4+/-delta}
• High-energy spin and charge excitations in electron-doped copper oxide superconductors
• Electronic Structure of Electron-doped Sm1.86Ce0.14CuO4: Strong `Pseudo-Gap' Effects, Nodeless Gap and Signatures of Short Range Order
• Membrane-based nanocalorimeter for high-resolution measurements of low-temperature specific heat
• Nodeless superconductivity arising from strong (pi,pi) antiferromagnetism in the infinite-layer electron-doped cuprate Sr1-xLaxCuO2

Cited by in corpus (12)

• The foot, the fan, and the cuprate phase diagram: Fermi-volume-changing quantum phase transitions
• Emergence of nodal Bogoliubov quasiparticles across the transition from the pseudogap metal to the d-wave superconductor
• Anomalous normal state gap in an electron-doped cuprate
• Deconfined quantum criticality of nodal $d$-wave superconductivity, Néel order, and charge order on the square lattice at half-filling
• van Hove Singularity-Driven Emergence of Multiple Flat Bands in Kagome Superconductors
• Fractionalized Fermi liquids and the cuprate phase diagram
• Quasiparticle scattering interference in cuprate superconductors
• Common behavior of the scaled condensation energy for both high-$T_c$ and conventional superconductors
• Unusual electronic structure in underdoped cuprate superconductors
• Inhomogeneous reduction-annealing effects on the electron-doped cuprate superconductor revealed by micro-focused angle-resolved photoemission spectroscopy
• Scaling behavior of superconductors
• Probing the pseudogap and beyond: Examining single-particle properties of the hole- and electron-doped Hubbard model