A momentum-dependent perspective on quasiparticle interference in Bi2Sr2CaCu2O8+δ

Abstract

Scanning tunnelling spectroscopy and angle-resolved photoemission spectroscopy are complementary probes, and yet the results of recent studies using these techniques on quasiparticle excitations in the copper oxide superconductors seem to be contradictory. In fact, there is no contradiction. Angle-resolved photoemission spectroscopy (ARPES) probes the momentum-space electronic structure of materials and provides invaluable information about the high-temperature superconducting cuprates1. Likewise, scanning tunnelling spectroscopy (STS) reveals the cuprates’ real-space inhomogeneous electronic structure. Recently, researchers using STS have exploited quasiparticle interference (QPI)—wave-like electrons that scatter off impurities to produce periodic interference patterns—to infer properties of the quasiparticles in momentum space. Surprisingly, some interference peaks in Bi2Sr2CaCu2O8+δ (Bi-2212) are absent beyond the antiferromagnetic zone boundary, implying the dominance of a particular scattering process2. Here, we show that ARPES detects no evidence of quasiparticle extinction: quasiparticle-like peaks are measured everywhere on the Fermi surface, evolving smoothly across the antiferromagnetic zone boundary. This apparent contradiction stems from differences in the nature of single-particle (ARPES) and two-particle (STS) processes underlying these probes. Using a simple model, we demonstrate extinction of QPI without implying the loss of quasiparticles beyond the antiferromagnetic zone boundary.