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

Angle-resolved photoemission spectroscopy (ARPES) probes the momentum-space electronic structure of materials and provides invaluable information about the high-temperature superconducting cuprates(1). 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+delta (Bi-2212) are absent beyond the anti-ferromagnetic zone boundary, implying the dominance of a particular scattering process(2). 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.