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Khajetoorians AA, Valentyuk M, Steinbrecher M, Schlenk T, Shick A, Kolorenc J, Lichtenstein AI, Wehling TO, Wiesendanger R, Wiebe J. Tuning emergent magnetism in a Hund's impurity. NATURE NANOTECHNOLOGY 2015; 10:958-64. [PMID: 26344182 DOI: 10.1038/nnano.2015.193] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 07/27/2015] [Indexed: 05/27/2023]
Abstract
The recently proposed concept of a Hund's metal--a metal in which electron correlations are driven by Hund's rule coupling-can be used to explain the exotic magnetic and electronic behaviour of strongly correlated electron systems of multi-orbital metallic materials. Tuning the abundance of parameters that determine these materials is, however, experimentally challenging. Here, we show that the basic constituent of a Hund's metal--a Hund's impurity--can be realized using a single iron atom adsorbed on a platinum surface, a system that comprises a magnetic moment in the presence of strong charge fluctuations. The magnetic properties can be controlled by using the tip of a scanning tunnelling microscope to change the binding site and degree of hydrogenation of the 3d transition-metal atom. We are able to experimentally explore a regime of four almost degenerate energy scales (Zeeman energy, temperature, Kondo temperature and magnetic anisotropy) and probe the magnetic excitations with the microscope tip. The regime of our Hund's impurity can be tuned from an emergent magnetic moment to a multi-orbital Kondo state, and the system could be used to test predictions of advanced many-body theories for non-Fermi liquids in quantum magnets or unconventional superconductors.
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Affiliation(s)
- A A Khajetoorians
- Department of Physics, Hamburg University, Hamburg D-20355, Germany
- Institute for Molecules and Materials (IMM), Radboud University, Nijmegen 6525 AJ, The Netherlands
| | - M Valentyuk
- Institute of Theoretical Physics, Hamburg University, Hamburg D-20355, Germany
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Ekaterinburg 620002, Russia
| | - M Steinbrecher
- Department of Physics, Hamburg University, Hamburg D-20355, Germany
| | - T Schlenk
- Department of Physics, Hamburg University, Hamburg D-20355, Germany
| | - A Shick
- Institute of Physics, ASCR, Na Slovance 2, Prague CZ-18221, Czech Republic
| | - J Kolorenc
- Institute of Physics, ASCR, Na Slovance 2, Prague CZ-18221, Czech Republic
| | - A I Lichtenstein
- Institute of Theoretical Physics, Hamburg University, Hamburg D-20355, Germany
| | - T O Wehling
- Institute for Theoretical Physics, Bremen Center for Computational Material Science, University of Bremen, Bremen D-28359, Germany
| | - R Wiesendanger
- Department of Physics, Hamburg University, Hamburg D-20355, Germany
| | - J Wiebe
- Department of Physics, Hamburg University, Hamburg D-20355, Germany
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Dubout Q, Donati F, Wäckerlin C, Calleja F, Etzkorn M, Lehnert A, Claude L, Gambardella P, Brune H. Controlling the spin of co atoms on pt(111) by hydrogen adsorption. PHYSICAL REVIEW LETTERS 2015; 114:106807. [PMID: 25815958 DOI: 10.1103/physrevlett.114.106807] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Indexed: 06/04/2023]
Abstract
We investigate the effect of H adsorption on the magnetic properties of individual Co atoms on Pt(111) with scanning tunneling microscopy. For pristine Co atoms, we detect no inelastic features in the tunnel spectra. Conversely, CoH and CoH2 show a number of low-energy vibrational features in their differential conductance identified by isotope substitution. Only the fcc-adsorbed species present conductance steps of magnetic origin, with a field splitting identifying their effective spin as Seff=2 for CoH and 3/2 for CoH2. The exposure to H2 and desorption through tunnel electrons allow the reversible control of the spin in half-integer steps. Because of the presence of the surface, the hydrogen-induced spin increase is opposite to the spin sequence of CoHn molecules in the gas phase.
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Affiliation(s)
- Q Dubout
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - F Donati
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - C Wäckerlin
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - F Calleja
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Calle Faraday 9, Campus Cantoblanco, E-28049 Madrid, Spain
| | - M Etzkorn
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - A Lehnert
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - L Claude
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - P Gambardella
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
- Department of Materials, ETH Zürich, Hönggerbergring 64, CH-8093 Zürich, Switzerland
| | - H Brune
- Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015 Lausanne, Switzerland
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Tsukahara N, Minamitani E, Kim Y, Kawai M, Takagi N. Controlling orbital-selective Kondo effects in a single molecule through coordination chemistry. J Chem Phys 2014; 141:054702. [PMID: 25106595 DOI: 10.1063/1.4890654] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Noriyuki Tsukahara
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | | | - Yousoo Kim
- RIKEN, 2-1 Hirosawa, Saitama 351-0198, Japan
| | - Maki Kawai
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Noriaki Takagi
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
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Abstract
We demonstrate the ability to measure the energy required to flip the spin of single adsorbed atoms. A low-temperature, high-magnetic field scanning tunneling microscope was used to measure the spin excitation spectra of individual manganese atoms adsorbed on Al2O3 islands on a NiAl surface. We find pronounced variations of the spin-flip spectra for manganese atoms in different local environments.
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Affiliation(s)
- A J Heinrich
- IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
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Gregory S. Experimental observation of scattering of tunneling electrons by a single magnetic moment. PHYSICAL REVIEW LETTERS 1992; 68:2070-2073. [PMID: 10045296 DOI: 10.1103/physrevlett.68.2070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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