• Hofmann, Philip
• Bianchi, Marco
• Esben, Juel Porat
• Rudenko, Alexander N.
• Mosina, Kseniia
• Rösner, Malte
• Sofer, Zdeněk
• Chen, Yong P.
• Klein, Julian
• Katsnelson, Mikhail I.
• Dirnberger, Florian
• Hsieh, Kimberly

Abstract

Ultrathin CrSBr flakes are exfoliated in situ on Au(111) and Ag(111) and their electronic structure is studied by angle-resolved photoemission spectroscopy. The thin flakes' electronic properties are drastically different from those of the bulk material and also substrate dependent. For both substrates, a strong charge transfer to the flakes is observed, partly populating the conduction band and giving rise to a highly anisotropic Fermi contour with an Ohmic contact to the substrate. The fundamental CrSBr band gap is strongly renormalized compared to the bulk. The charge transfer to the CrSBr flake is substantially larger for Ag(111) than for Au(111), but a rigid energy shift of the chemical potential is insufficient to describe the observed band structure modifications. In particular, the Fermi contour shows a Lifshitz transition, the fundamental band gap undergoes a transition from direct on Au(111) to indirect on Ag(111) and a doping-induced symmetry breaking between the intralayer Cr magnetic moments further modifies the band structure. Electronic structure calculations can account for nonrigid Lifshitz-type band structure changes in thin CrSBr as a function of doping and strain. In contrast to undoped bulk band structure calculations that require self-consistent GW theory, the doped thin film properties are well approximated by density functional theory if local Coulomb interactions are taken into account on the mean-field level and the charge transfer is considered.

Topics

• density
• impedance spectroscopy
• theory
• thin film
• anisotropic
• density functional theory
• band structure