High-Energy Anomaly in the Band Dispersion of the Ruthenate Superconductor

Iwasawa Hideaki

Yoshida Yoshiyuki

Hase Izumi

Shimada Kenya

Namatame Hirofumi

Taniguchi Masaki

Aiura Yoshihiro

Physical Review Letters

We reveal a “high-energy anomaly" (HEA) in the band dispersion of the unconventional ruthenate superconductor Sr2RuO4, by means of high-resolution angle-resolved photoemission spectroscopy (ARPES) with tunable energy and polarization of incident photons. This observation provides another class of correlated materials exhibiting this anomaly beyond high-Tc cuprates. We demonstrate that two distinct types of band renormalization associated with and without the HEA occur as a natural consequence of the energetics in the bandwidth and the energy scale of the HEA. Our results are well reproduced by a simple analytical form of the self-energy based on the Fermi-liquid theory, indicating that the HEA exists at a characteristic energy scale of the multielectron excitations. We propose that the HEA universally emerges if the systems have such a characteristic energy scale inside of the bandwidth.

物理学 [ 420 ]

英語

American Physical Society

(c) 2012 American Physical Society

[ISSN] 0031-9007

[DOI] 10.1103/PhysRevLett.109.066404

[NCID] AA00773679

[DOI] http://dx.doi.org/10.1103/PhysRevLett.109.066404