Tracing the localization of 4 f electrons: Angle-resolved photoemission on YbCo2Si2, the stable trivalent counterpart of the heavy-fermion YbRh2Si2

Article

DOI  :  10.1103/PhysRevB.90.195138

来源: SCIE

【 摘 要 】

YbCo2Si2 is considered to serve as a stable-valent, isoelectronic reference for the extensively studied heavy-fermion system YbRh2Si2 which is situated very close to an antiferromagnetic quantum critical point (QCP). The investigation of the Fermi surface (FS) topology of YbCo2Si2 and its comparison to YbRh2Si2 could help to unravel the strongly disputed nature of this quantum phase transition, whether it originates from a local or itinerant QCP. Here we study the electronic structure and FS of YbCo2Si2 by means of angle-resolved photoelectron spectroscopy (ARPES) and compare it to ab initio band structure calculations and FS modeling. Our approach allows the electronic structure at the surface and in the bulk to be disentangled. Identifying the bulk contribution, we demonstrate that YbCo2Si2 exhibits a small FS, confirming the formation of a large FS in YbRh2Si2. This favors an itinerant QCP, instead of the widely discussed local scenario. Our study demonstrates that ARPES is a reliable tool for the study of bulk electronic states in intermetallic Kondo lattice systems despite the complexity induced by their three-dimensional character and the presence of pronounced surface states.

【 授权许可】

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