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Quantum Magnetism - Spinons, Skyrmions and Dipoles

English title Quantum Magnetism - Spinons, Skyrmions and Dipoles
Applicant Ronnow Henrik M.
Number 146870
Funding scheme Project funding (Div. I-III)
Research institution Laboratoire de magnétisme quantique EPFL - SB - IPMC - LQM
Institution of higher education EPF Lausanne - EPFL
Main discipline Condensed Matter Physics
Start/End 01.04.2013 - 31.05.2016
Approved amount 672'750.00
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Keywords (5)

quantum magnetism; neutron scattering; Magnetism; magneto-elastic; phonons

Lay Summary (French)

Lead
Le magnétisme quantique est un domaine à la pointe de la physique de la matière condensée. D'une part, il fournit le cadre idéal pour développer et tester de nouveaux concepts fondamentaux dans les domaines de la physique des solides et des statistiques, d'autre part il a un rôle central dans l’émergence de plusieurs classes de matériaux avec de nouvelles propriétés électroniques.
Lay summary

Ce projet de recherche fondamentale porte sur 4 thèmes passionnants :

1. Le modèle fondamental 2D Heisenberg qui inclut la compréhension de l’avancement du spectre d'excitation et son extension liés aux cuprates non dopés et faiblement dopés

2. L’émergence du composant magnétoélectrique Cu2OSeO3 qui accueille un treillis de skyrmion qui peut être contrôlé par des champs électriques

3. Exploration des dipolaires couplées avec des modèles de systèmes magnétiques LiREF4

4. Achèvement d'un unique magnétomètre à ultra-basse température SQUID

Direct link to Lay Summary Last update: 09.04.2013

Lay Summary (English)

Lead
Quantum magnetism remains at the forefront of condensed matter physics. On one hand, it provides the ideal arena for developing and testing new fundamental concepts in solid-state and statistical physics, on the other hand it has a pivotal role in several classes of emerging materials with new electronic properties.
Lay summary

This fundamental research project addresses 4 exciting topics:

A The fundamental 2D Heisenberg model, advancing understanding of the excitation spectrum and its extension to undoped and weakly doped cuprates

B The emerging magnetoelectric compound Cu2OSeO3, hosting a skyrmion lattice that can be controlled by electric fields

C Exploration of dipolar coupled magnetic model systems LiREF4

D Completion of a unique ultra-low temperature SQUID magnetometer

Direct link to Lay Summary Last update: 09.04.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Dramatic pressure-driven enhancement of bulk skyrmion stability
Levatić I., Popčević P., Šurija V., Kruchkov A., Berger H., Magrez A., White J. S., Rønnow H. M., Živković I. (2016), Dramatic pressure-driven enhancement of bulk skyrmion stability, in Scientific Reports, 6, 21347-21347.
Origin of the Spin-Orbital Liquid State in a Nearly J=0 Iridate Ba3ZnIr2O9
Nag Abhishek, Middey S., Bhowal Sayantika, Panda S. K., Mathieu Roland, Orain J. C., Bert F., Mendels P., Freeman P. G., Mansson M., Ronnow H. M., Telling M., Biswas P. K., Sheptyakov D., Kaushik S. D., Siruguri Vasudeva, Meneghini Carlo, Sarma D. D., Dasgupta Indra, Ray Sugata (2016), Origin of the Spin-Orbital Liquid State in a Nearly J=0 Iridate Ba3ZnIr2O9, in Physical Review Letters, 116(9), 097205.
Spin excitations in the skyrmion host Cu2OSeO3
Tucker G. S., White J. S., Romhányi J., Szaller D., Kézsmárki I., Roessli B., Stuhr U., Magrez A., Groitl F., Babkevich P., Huang P., Živković I., Rønnow H. M. (2016), Spin excitations in the skyrmion host Cu2OSeO3, in Physical Review B, 93(5), 054401.
A new class of chiral materials hosting magnetic skyrmions beyond room temperature
Tokunaga Y., Yu X. Z., White J. S., Ronnow H. M., Morikawa D., Taguchi Y., Tokura Y. (2015), A new class of chiral materials hosting magnetic skyrmions beyond room temperature, in NATURE COMMUNICATIONS, 6, 7638.
Crystal Structure, Transport, and Magnetic Properties of an Ir6+ Compound Ba8Al2IrO14
Yang Lin, Pisoni Andrea, Magrez Arnaud, Katrych Sergiy, Arakcheeva Alla, Dalla Piazza Bastien, Prsa Krunoslav, Jacimovic Jacim, Akrap Ana, Teyssier Jeremie, Forro Laszlo, Ronnow Henrik M. (2015), Crystal Structure, Transport, and Magnetic Properties of an Ir6+ Compound Ba8Al2IrO14, in INORGANIC CHEMISTRY, 54(9), 4371-4376.
Evidence of quantum dimer excitations in Sr3Ir2O7
Sala M. Moretti, Schnells V., Boseggia S., Simonelli L., Al-Zein A., Vale J. G., Paolasini L., Hunter E. C., Perry R. S., Prabhakaran D., Boothroyd A. T., Krisch M., Monaco G., Ronnow H. M., McMorrow D. F., Mila F. (2015), Evidence of quantum dimer excitations in Sr3Ir2O7, in PHYSICAL REVIEW B, 92(2), 024405.
Filming the formation and fluctuation of skyrmion domains by cryo-Lorentz transmission electron microscopy
Rajeswari Jayaraman, Huang Ping, Mancini Giulia Fulvia, Murooka Yoshie, Latychevskaia Tatiana, McGrouther Damien, Cantoni Marco, Baldini Edoardo, White Jonathan Stuart, Magrez Arnaud, Giamarchi Thierry, Ronnow Henrik Moodysson, Carbone Fabrizio (2015), Filming the formation and fluctuation of skyrmion domains by cryo-Lorentz transmission electron microscopy, in PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 112(46), 14212-14217.
Filming the formation and fluctuation of skyrmion domains by cryo-Lorentz transmission electron microscopy
Rajeswari Jayaraman, Huang Ping, Mancini Giulia Fulvia, Murooka Yoshie, Latychevskaia Tatiana, McGrouther Damien, Cantoni Marco, Baldini Edoardo, White Jonathan Stuart, Magrez Arnaud, Giamarchi Thierry, Rønnow Henrik Moodysson, Carbone Fabrizio (2015), Filming the formation and fluctuation of skyrmion domains by cryo-Lorentz transmission electron microscopy, in Proceedings of the National Academy of Sciences, 112(46), 14212-14217.
Fractional excitations in the square-lattice quantum antiferromagnet
Piazza B. Dalla, Mourigal M., Christensen N. B., Nilsen G. J., Tregenna-Piggott P., Perring T. G., Enderle M., McMorrow D. F., Ivanov D. A., Ronnow H. M. (2015), Fractional excitations in the square-lattice quantum antiferromagnet, in NATURE PHYSICS, 11(1), 62-68.
Magnetic model in multiferroic NdFe3(BO3)(4) investigated by inelastic neutron scattering
Hayashida S., Soda M., Itoh S., Yokoo T., Ohgushi K., Kawana D., Ronnow H. M., Masuda T. (2015), Magnetic model in multiferroic NdFe3(BO3)(4) investigated by inelastic neutron scattering, in PHYSICAL REVIEW B, 92(5), 054402.
Magnons in tetragonal CuO
Moser S., Shaik N. E., Samal D., Fatale S., Dalla Piazza B., Dantz M., Pelliciari J., Olalde-Velasco P., Schmitt T., Koster G., Mila F., Ronnow H. M., Grioni M. (2015), Magnons in tetragonal CuO, in PHYSICAL REVIEW B, 92(14), 140404.
Neel-type skyrmion lattice with confined orientation in the polar magnetic semiconductor GaV4S8
Kezsmarki I., Bordacs S., Milde P., Neuber E., Eng L. M., White J. S., Ronnow H. M., Dewhurst C. D., Mochizuki M., Yanai K., Nakamura H., Ehlers D., Tsurkan V., Loidl A. (2015), Neel-type skyrmion lattice with confined orientation in the polar magnetic semiconductor GaV4S8, in NATURE MATERIALS, 14(11), 1116-1116.
Neutron spectroscopic study of crystal-field excitations and the effect of the crystal field on dipolar magnetism in LiRF4 (R = Gd, Ho, Er, Tm, and Yb)
Babkevich P., Finco A., Jeong M., Piazza B. Dalla, Kovacevic I., Klughertz G., Kraemer K. W., Kraemer C., Adroja D. T., Goremychkin E., Unruh T., Straessle T., Di Lieto A., Jensen J., Ronnow H. M. (2015), Neutron spectroscopic study of crystal-field excitations and the effect of the crystal field on dipolar magnetism in LiRF4 (R = Gd, Ho, Er, Tm, and Yb), in PHYSICAL REVIEW B, 92(14), 144422.
One-dimensional quantum magnetism in the anhydrous alum KTi(SO4)(2)
Nilsen G. J., Araja A., Tsirlin A. A., Mutka H., Kasinathan D., Ritter C., Ronnow H. M. (2015), One-dimensional quantum magnetism in the anhydrous alum KTi(SO4)(2), in NEW JOURNAL OF PHYSICS, 17, 113035.
Pressure induced evolution of superconductivity and magnetic hourglass dispersion in Fe1.02Te0.7Se0.3
Lancon D., Tsyrulin N., Boehm M., Viennois R., Zabihzadeh S., Kusmartseva A., Giannini E., Ronnow H M (2015), Pressure induced evolution of superconductivity and magnetic hourglass dispersion in Fe1.02Te0.7Se0.3, in NEW JOURNAL OF PHYSICS, 17, 043020.
Quantum critical scaling for a Heisenberg spin-1/2 chain around saturation
Jeong M., Ronnow H. M. (2015), Quantum critical scaling for a Heisenberg spin-1/2 chain around saturation, in PHYSICAL REVIEW B, 92(18), 180409.
Spin-orbit-induced orbital excitations in Sr2RuO4 and Ca2RuO4: A resonant inelastic x-ray scattering study
Fatuzzo C. G., Dantz M., Fatale S., Olalde-Velasco P., Shaik N. E., Piazza B. Dalla, Toth S., Pelliciari J., Fittipaldi R., Vecchione A., Kikugawa N., Brooks J. S., Ronnow H. M., Grioni M., Rueegg Ch., Schmitt T., Chang J. (2015), Spin-orbit-induced orbital excitations in Sr2RuO4 and Ca2RuO4: A resonant inelastic x-ray scattering study, in PHYSICAL REVIEW B, 91(15), 155104.
Spin-orbit-induced orbital excitations in Sr2RuO4 and Ca2RuO4: A resonant inelastic x-ray scattering study (vol 91, 155104, 2015)
Fatuzzo C. G., Dantz M., Fatale S., Olalde-Velasco P., Shaik N. E., Dalla Piazza B., Toth S., Pelliciari J., Fittipaldi R., Vecchione A., Kikugawa N., Brooks J. S., Ronnow H. M., Grioni M., Rueegg Ch., Schmitt T., Chang J. (2015), Spin-orbit-induced orbital excitations in Sr2RuO4 and Ca2RuO4: A resonant inelastic x-ray scattering study (vol 91, 155104, 2015), in PHYSICAL REVIEW B, 91(19), 155104.
The use of selected neutron absorption resonance filters to suppress spurious events on hot neutron spectrometers
Lancon D., Ewings R. A., Stewart J. R., Jimenez-Ruiz M., Ronnow H. M. (2015), The use of selected neutron absorption resonance filters to suppress spurious events on hot neutron spectrometers, in NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND, 780, 9-14.
An ultra-low temperature scanning Hall probe microscope for magnetic imaging below 40 mK
Karci Ozgur, Piatek Julian O., Jorba Pau, Dede Munir, Ronnow Henrik M., Oral Ahmet (2014), An ultra-low temperature scanning Hall probe microscope for magnetic imaging below 40 mK, in REVIEW OF SCIENTIFIC INSTRUMENTS, 85(10), 103703.
Anisotropic softening of magnetic excitations along the nodal direction in superconducting cuprates
Guarise M., Dalla Piazza B., Berger H., Giannini E., Schmitt T., Ronnow H. M., Sawatzky G. A., van den Brink J., Altenfeld D., Eremin I., Grioni M. (2014), Anisotropic softening of magnetic excitations along the nodal direction in superconducting cuprates, in NATURE COMMUNICATIONS, 5, 6760.
Bilayer splitting and wave functions symmetry in Sr3Ir2O7
Moreschini L., Moser S., Ebrahimi A., Dalla Piazza B., Kim K. S., Boseggia S., McMorrow D. F., Ronnow H. M., Chang J., Prabhakaran D., Boothroyd A. T., Rotenberg E., Bostwick A., Grioni M. (2014), Bilayer splitting and wave functions symmetry in Sr3Ir2O7, in PHYSICAL REVIEW B, 89(20), 201114.
Chirality of structure and magnetism in the magnetoelectric compound Cu2OSeO3
Dyadkin V., Prsa K., Grigoriev S. V., White J. S., Huang P., Ronnow H. M., Magrez A., Dewhurst C. D., Chernyshov D. (2014), Chirality of structure and magnetism in the magnetoelectric compound Cu2OSeO3, in PHYSICAL REVIEW B, 89(14), 140409.
Correlated Decay of Triplet Excitations in the Shastry-Sutherland Compound SrCu2(BO3)(2)
Zayed M. E., Rueegg Ch., Straessle Th., Stuhr U., Roessli B., Ay M., Mesot J., Link P., Pomjakushina E., Stingaciu M., Conder K., Ronnow H. M. (2014), Correlated Decay of Triplet Excitations in the Shastry-Sutherland Compound SrCu2(BO3)(2), in PHYSICAL REVIEW LETTERS, 113(6), 067201.
Critical scaling in the cubic helimagnet Cu2OSeO3
Zivkovic I., White J. S., Ronnow H. M., Prsa K., Berger H. (2014), Critical scaling in the cubic helimagnet Cu2OSeO3, in PHYSICAL REVIEW B, 89(6), 060401.
Electric-Field-Induced Skyrmion Distortion and Giant Lattice Rotation in the Magnetoelectric Insulator Cu2OSeO3
White J. S., Prsa K., Huang P., Omrani A. A., Zivkovic I., Bartkowiak M., Berger H., Magrez A., Gavilano J. L., Nagy G., Zang J., Ronnow H. M. (2014), Electric-Field-Induced Skyrmion Distortion and Giant Lattice Rotation in the Magnetoelectric Insulator Cu2OSeO3, in PHYSICAL REVIEW LETTERS, 113(10), 107203.
Exploration of the helimagnetic and skyrmion lattice phase diagram in Cu2OSeO3 using magnetoelectric susceptibility
Omrani A. A., White J. S., Prsa K., Zivkovic I., Berger H., Magrez A., Liu Ye-Hua, Han J. H., Ronnow H. M. (2014), Exploration of the helimagnetic and skyrmion lattice phase diagram in Cu2OSeO3 using magnetoelectric susceptibility, in PHYSICAL REVIEW B, 89(6), 064406.
Nodal Landau Fermi-liquid quasiparticles in overdoped La1.77Sr0.23CuO4
Fatuzzo C. G., Sassa Y., Mansson M., Pailhes S., Lipscombe O. J., Hayden S. M., Patthey L., Shi M., Grioni M., Ronnow H. M., Mesot J., Tjernberg O., Chang J. (2014), Nodal Landau Fermi-liquid quasiparticles in overdoped La1.77Sr0.23CuO4, in PHYSICAL REVIEW B, 89(20), 205104.
Nonequilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar-coupled spin-glass LiHo0.5Er0.5F4
Piatek J. O., Kovacevic I., Babkevich P., Piazza B. Dalla, Neithardt S., Gavilano J., Kraemer K. W., Ronnow H. M. (2014), Nonequilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar-coupled spin-glass LiHo0.5Er0.5F4, in PHYSICAL REVIEW B, 90(17), 174427.
Note: Versatile sample stick for neutron scattering experiments in high electric fields
Bartkowiak M., White J. S., Ronnow H. M., Prsa K. (2014), Note: Versatile sample stick for neutron scattering experiments in high electric fields, in REVIEW OF SCIENTIFIC INSTRUMENTS, 85(2), 026112.
Quantum and thermal ionic motion, oxygen isotope effect, and superexchange distribution in La2CuO4
Haefliger P. S., Gerber S., Pramod R., Schnells V. I., dalla Piazza B., Chati R., Pomjakushin V., Conder K., Pomjakushina E., Le Dreau L., Christensen N. B., Syljuasen O. F., Normand B., Ronnow H. M. (2014), Quantum and thermal ionic motion, oxygen isotope effect, and superexchange distribution in La2CuO4, in PHYSICAL REVIEW B, 89(8), 085113.
Temperature dependence of the pressure induced monoclinic distortion in the spin S=1/2 Shastry-Sutherland compound SrCu2(BO3)(2)
Zayed M. E., Rueegg Ch., Pomjakushina E., Stingaciu M., Conder K., Hanfland M., Merlini M., Ronnow H. M. (2014), Temperature dependence of the pressure induced monoclinic distortion in the spin S=1/2 Shastry-Sutherland compound SrCu2(BO3)(2), in SOLID STATE COMMUNICATIONS, 186, 13-17.
The electronic structure of the high-symmetry perovskite iridate Ba2IrO4
Moser S., Moreschini L., Ebrahimi A., Dalla Piazza B., Isobe M., Okabe H., Akimitsu J., Mazurenko V. V., Kim K. S., Bostwick A., Rotenberg E., Chang J., Ronnow H. M., Grioni M. (2014), The electronic structure of the high-symmetry perovskite iridate Ba2IrO4, in NEW JOURNAL OF PHYSICS, 16, 013008.
Electronic structure of KTi(SO4)(2)center dot H2O: An S=1/2 frustrated chain antiferromagnet
Kasinathan Deepa, Koepernik K., Janson O., Nilsen G. J., Piatek J. O., Ronnow H. M., Rosner H. (2013), Electronic structure of KTi(SO4)(2)center dot H2O: An S=1/2 frustrated chain antiferromagnet, in PHYSICAL REVIEW B, 88(22), 224410.
Field-Induced Quantum Soliton Lattice in a Frustrated Two-Leg Spin-1/2 Ladder
Casola F., Shiroka T., Feiguin A., Wang S., Grbic M. S., Horvatic M., Kraemer S., Mukhopadhyay S., Conder K., Berthier C., Ott H. -R., Ronnow H. M., Rueegg Ch., Mesot J. (2013), Field-Induced Quantum Soliton Lattice in a Frustrated Two-Leg Spin-1/2 Ladder, in PHYSICAL REVIEW LETTERS, 110(18), 187201.
Fractional spinon excitations in the quantum Heisenberg antiferromagnetic chain
Mourigal Martin, Enderle Mechthild, Kloepperpieper Axel, Caux Jean-Sebastien, Stunault Anne, Ronnow Henrik M. (2013), Fractional spinon excitations in the quantum Heisenberg antiferromagnetic chain, in NATURE PHYSICS, 9(7), 435-441.
Glassy low-energy spin fluctuations and anisotropy gap in La1.88Sr0.12CuO4
Romer A. T., Chang J., Christensen N. B., Andersen B. M., Lefmann K., Maehler L., Gavilano J., Gilardi R., Niedermayer Ch., Ronnow H. M., Schneidewind A., Link P., Oda M., Ido M., Momono N., Mesot J. (2013), Glassy low-energy spin fluctuations and anisotropy gap in La1.88Sr0.12CuO4, in PHYSICAL REVIEW B, 87(14), 144513.
Low-temperature spin dynamics of a valence bond glass in Ba2YMoO6
de Vries M. A., Piatek J. O., Misek M., Lord J. S., Ronnow H. M., Bos J-W G. (2013), Low-temperature spin dynamics of a valence bond glass in Ba2YMoO6, in NEW JOURNAL OF PHYSICS, 15, 043024.
Phase diagram with an enhanced spin-glass region of the mixed Ising-XY magnet LiHoxEr1-xF4
Piatek J. O., Dalla Piazza B., Nikseresht N., Tsyrulin N., Zivkovic I., Kraemer K. W., Laver M., Prokes K., Matas S., Christensen N. B., Ronnow H. M. (2013), Phase diagram with an enhanced spin-glass region of the mixed Ising-XY magnet LiHoxEr1-xF4, in PHYSICAL REVIEW B, 88(1), 014408.
Spin-gap evolution upon Ca doping in the spin-ladder series Sr14-xCaxCu24O41 studied by inelastic neutron scattering
Deng G., Tsyrulin N., Bourges P., Lamago D., Ronnow H., Kenzelmann M., Danilkin S., Pomjakushina E., Conder K. (2013), Spin-gap evolution upon Ca doping in the spin-ladder series Sr14-xCaxCu24O41 studied by inelastic neutron scattering, in PHYSICAL REVIEW B, 88(1), 014504.
Temperature-dependent electron-phonon coupling in La2-xSrxCuO4 probed by femtosecond x-ray diffraction
Mansart B., Cottet M. J. G., Mancini G. F., Jarlborg T., Dugdale S. B., Johnson S. L., Mariager S. O., Milne C. J., Beaud P., Gruebel S., Johnson J. A., Kubacka T., Ingold G., Prsa K., Ronnow H. M., Conder K., Pomjakushina E., Chergui M., Carbone F. (2013), Temperature-dependent electron-phonon coupling in La2-xSrxCuO4 probed by femtosecond x-ray diffraction, in PHYSICAL REVIEW B, 88(5), 054507.

Collaboration

Group / person Country
Types of collaboration
Zagreb Institute of Physics Croatia (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Institut Laue Langevin, Grenoble France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Institute of Theoretical Physics, EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Department of Condensed Matter Physics, University of Geneva Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Institute of Condensed Matter Physics, EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Laboratory for Neutron Scattering, PSI Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel

Awards

Title Year
Springer thesis award 2016
Special distinction from the EPFL Doctorate Award selection committee 2015

Associated projects

Number Title Start Funding scheme
166298 Quantum Magnetism - Checkerboards, Skyrmions and Dipoles 01.06.2016 Project funding (Div. I-III)
162110 Harnessing Molecular Crystals for Quantum Magnets and Elucidating Quantum Critical Physics 01.03.2016 Bilateral programmes
157780 Liquid Helium cooled sample holder for TEM 01.01.2015 R'EQUIP
130522 Quantum Magnetism - Dimer Physics and Dipolar Criticality 01.04.2010 Project funding (Div. I-III)
130522 Quantum Magnetism - Dimer Physics and Dipolar Criticality 01.04.2010 Project funding (Div. I-III)
157771 Cryofree magnet with variable temperature insert 01.02.2015 R'EQUIP
166271 Nonlinear Probes of quantum localized systems 01.03.2017 Project funding (Div. I-III)
160765 Mott Physics Beyond the Heisenberg Model in Iridates and Related Materials 01.01.2016 Sinergia
141962 Mott Physics Beyond the Heisenberg Model in Iridates and Related Materials 01.01.2013 Sinergia
144972 High efficiency neutron spectrometer optimized for investigations under extreme conditions 01.01.2014 R'EQUIP
126751 Nanofabricated devices based on intrinsically layered correlated electron materials 01.12.2009 Project funding (Div. I-III)
132877 Magnetic Excitations in Low-Dimensional Arrays of Quantum Spins 01.01.2011 Project funding (Div. I-III)
133815 Setup for studies of quantum phenomena in condensed matter systems at ultra-low temperatures in magnetic vector fields 01.04.2012 R'EQUIP
121397 Sub-Kelvin high sensitivity magnetometer for magnetic materials exploration 01.07.2008 R'EQUIP
164013 Laser-heated Floating Zone Furnace for EPFL Crystal Growth Facility 01.11.2016 R'EQUIP

Abstract

Quantum magnetism remains at the forefront of condensed matter physics. On one hand, it provides the ideal arena for developing and testing new fundamental concepts in solid-state and statistical physics, on the other hand it has a pivotal role in several classes of emerging materials with new electronic properties.Here we propose four research topics:A The fundamental 2D Heisenberg model, advancing understanding of the excitation spectrum and its extension to undoped and weakly doped cupratesB The emerging magnetoelectric compound Cu2OSeO3, hosting a skyrmion lattice that can be controlled by electric fieldsC Exploration of dipolar coupled magnetic model systems LiREF4D Completion of a unique ultra-low temperature SQUID magnetometerThe four sub-projects are propelled by four PhD students each acquiring their specialization in respectively scattering techniques, imaging, low-temperature measurements and theory, which they combine in a horizontal cross-subject team structure. For sub-projects A and C, special pivotal expertise is brought in by the two co-applicants.
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