Energy band and spin-dependent many-body interactions in ferromagnetic Ni(110): A high-resolution angle-resolved photoemission study

Abstract

High-resolution angle-resolved photoelectron spectroscopy of ferromagnetic Ni͑110͒ has been conducted to elucidate energy band and spin-dependent many-body interactions. A kink structure has been clearly observed in the energy band dispersions of the minority spin ⌺ 2↓ and ⌺ 1↓ , while it is absent in the majority spin ⌺ 1↑ band. Analyses of the self-energy indicate that the kink originates from the electron-phonon interaction. Based on a detailed study of the effective mass enhancement, we find that the electron-phonon interaction and electron correlation contribute to the spectral features near the Fermi level in different ways, depending on the identity of the energy band and the spin direction. These results provide insight into the interplay of these many-body interactions on quasiparticles near the Fermi level.

Isotropic Kink and Quasiparticle Excitations in the Three-Dimensional Perovskite ManganiteLa0.6Sr0.4MnO3Horiba1, Kitamura2, Yoshimatsu3 et al. 2016Phys. Rev. Lett.19290View full textAdd to dashboardCite

“…In addition, the hole band of the LSMO, which was predicted by the LDA calculations [15,22] respectively, which were obtained from the MDCs using these equations. The overall line shapes of both ReΣ(ω) and ImΣ(ω) are similar to those observed in the surface bands of the transition metals [6,8,10]. This suggests that the origin of the kink in the ARPES band is an electron-boson coupling as in the case of the transition-metal surface bands.…”

High-resolution angle-resolved photoemission study of Ni(1 1 1) surface state

“…Furthermore, on the basis of the detailed line shape analyses, it is possible to experimentally evaluate the self-energy R, in which all the many-body interactions are included. One can discuss the strength of many-body interaction such as electron-electron and electron-phonon interactions on each of the FSs [9,10].…”

‘True’ bosonic coupling strength in strongly correlated superconductors

“…However, the derivation of the self-energy depends on the unfounded assumption of a bare band, which cannot be directly observed. To overcome this difficulty, the self-consistency of the self-energy via Kramers-Kronig relation is the most widely used criteria to extract the self-energy25678. Moreover, iterative fitting algorithms for the determination of the bare band have also been developed based on the maximum entropy method91011 or the Kramers-Kronig relation121314.…”