Structure and Magnetism of EuS on Bi2Se3(0001). Issue 1 (13th August 2020)

• Record Type: Journal Article
• Authors: Meyerheim, Holger L.; Ernst, Arthur; Mohseni, Katayoon; Polyakov, Andrey; Maznichenko, Igor V.; Buczek, Pawel A.; Coati, Alessandro; Parkin, Stuart S. P.
• Other Names: Rader Oliver guestEditor.; Bihlmayer Gustav guestEditor.; Fischer Saskia F. guestEditor.
• Is Part Of: Physica status solidi. Volume 258:Issue 1(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-13
• Subjects: europium sulfide -- proximity -- surface X‐ray diffraction -- topological insulators; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.202000290
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : The rocksalt‐type ferromagnetic (FM) insulator EuS (bulk T C = 17 K) grown on Bi2 Se3 with well‐matched (111) plane of the film and (0001) plane of the substrate is studied. The system may feature magnetic proximity effect breaking the time‐reversal symmetry and opening a bandgap in the metallic topologically protected surface state of Bi2 Se3 . The experimental X‐ray diffraction studies are combined with ab initio calculations to resolve contradictory results concerning the enhancement of the T C up to 300 K and the degree of induced magnetization in the system. It is concluded that previous studies relied on idealized and unconfirmed structure models. Herein, it is shown by surface X‐ray diffraction (SXRD) with ab initio calculations that a two double layer‐thick EuS film grows with a sharp interface and without chemical intermixing in a single domain state in an FCC‐type stacking on the Bi2 Se3 (0001) surface in which the topmost layer is metallic, thereby lifting polarity. A large p z ‐orbital‐derived top‐layer sulfur magnetic moment of 0.6 μB is found, whereas for europium, μ Eu = 6.9 μB throughout the film is found. No magnetization within the first Bi2 Se3 quintuple layer is found. The calculation of the exchange parameters J ij indicates a complex FM and antiferromagnetic ordering between europium and sulfur with a maximum Néel temperature of 226 K. Abstract : Structure and magnetism of two EuS double layers on Bi2 Se3 (0001) is studied. EuS grows with a sharp interface without chemical intermixing in ABCA‐type sequence. Magnetic order is due to exchange interaction between top layer sulfur p z ‐orbitals. Calculated exchange parameters indicate a complex ferromagnetic and antiferromagnetic ordering between Eu and S moments with T N = 226 K.