title: Robust and tunable itinerant ferromagnetism at the silicon surface of the antiferromagnet GdRh2Si2.
abstract: Spin-polarized two-dimensional electron states (2DESs) at surfaces and interfaces of magnetically active materials attract immense interest because of the idea of exploiting fermion spins rather than charge in next generation electronics. Applying angle-resolved photoelectron spectroscopy, we show that the silicon surface of GdRh2Si2 bears two distinct 2DESs, one being a Shockley surface state, and the other a Dirac surface resonance. Both are subject to strong exchange interaction with the ordered 4f-moments lying underneath the Si-Rh-Si trilayer. The spin degeneracy of the Shockley state breaks down below ~90 K, and the splitting of the resulting subbands saturates upon cooling at values as high as ~185 meV. The spin splitting of the Dirac state becomes clearly visible around ~60 K, reaching a maximum of ~70 meV. An abrupt increase of surface magnetization at around the same temperature suggests that the Dirac state contributes significantly to the magnetic properties at the Si surface. We also show the possibility to tune the properties of 2DESs by depositing alkali metal atoms. The unique temperature-dependent ferromagnetic properties of the Si-terminated surface in GdRh2Si2 could be exploited when combined with functional adlayers deposited on top for which novel phenomena related to magnetism can be anticipated.
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.|CSNSM, University Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay, France.
authors.forename: M
authors.initials: M
authors.lastname: Güttler
authors.affiliation: MAX IV Laboratory, Lund University, Box 118, 22100 Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Generalov
authors.affiliation: Donostia International Physics Center (DIPC), Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, 20080 San Sebastian, Spain.|Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia.
authors.forename: M M
authors.initials: MM
authors.lastname: Otrokov
authors.affiliation: European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, France.
authors.forename: K
authors.initials: K
authors.lastname: Kummer
authors.affiliation: Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Straße 1, 60438 Frankfurt am Main, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Kliemt
authors.affiliation: IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Fedorov
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Chikina
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Danzenbächer
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schulz
authors.affiliation: Donostia International Physics Center (DIPC), Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, 20080 San Sebastian, Spain.|Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia.|Saint Petersburg State University, Saint Petersburg 198504, Russia.
authors.forename: E V
authors.initials: EV
authors.lastname: Chulkov
authors.affiliation: Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia.|Institute of Strength Physics and Materials Science, RAS, 634021 Tomsk, Russia.
authors.forename: Yu M
authors.initials: YM
authors.lastname: Koroteev
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, D-01187 Dresden, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Caroca-Canales
authors.affiliation: Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Shi
authors.affiliation: Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland.|SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Radovic
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, D-01187 Dresden, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Geibel
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Laubschat
authors.affiliation: Diamond Light Source, Didcot OX11 0DE, UK.
authors.forename: P
authors.initials: P
authors.lastname: Dudin
authors.affiliation: Diamond Light Source, Didcot OX11 0DE, UK.
authors.forename: T K
authors.initials: TK
authors.lastname: Kim
authors.affiliation: Diamond Light Source, Didcot OX11 0DE, UK.
authors.forename: M
authors.initials: M
authors.lastname: Hoesch
authors.affiliation: Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Straße 1, 60438 Frankfurt am Main, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Krellner
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany.|Donostia International Physics Center (DIPC), Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, 20080 San Sebastian, Spain.|Saint Petersburg State University, Saint Petersburg 198504, Russia.|IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain.
authors.forename: D V
authors.initials: DV
authors.lastname: Vyalikh