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Spin Liquids and Proximate Phases in Frustrated Magnets

Applicant Simutis Gediminas
Number 178604
Funding scheme Early Postdoc.Mobility
Research institution Laboratoire de Physique des Solides Université de Paris-Sud associé au CNRS (URA 2)
Institution of higher education Institution abroad - IACH
Main discipline Condensed Matter Physics
Start/End 01.11.2018 - 30.06.2020
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Keywords (6)

Magnetism; Frustration; NMR; muSR; Strong Correlations; Spin Liquid

Lay Summary (German)

Lead
Wenn man magnetische Momente in ungewöhnliche Anordnung bringt, zeigen sie neuartige Eigenschaften. In diesem Projekt werden wir verschiedene magnetische Gitter durch externe Einflüsse modifizieren und dadurch Kontrolle über ihre Eigenschaften erlangen.
Lay summary

Magneten sind in unserer Welt allgegenwärtig. Wir nutzen sie nicht nur Dinge am Kühlschrank zu befestigen, sondern auch um unsere Daten auf der Festplatte unseres Computers zu speichern. Ihre interessantesten Eigenschaften zeigen sich jedoch, wenn ihre magnetischen Momente in komplexe Anordnungen gebracht werden. Ein besonders interessanter Fall tritt ein, wenn die Gesetze, welche die Interaktion zwischen den magnetischen Momenten bestimmen, nicht alle gleichzeitig erfüllt werden können. Die sogenannten „frustrierten Magneten“ weisen einen einzigartigen, exotischen Grundzustand auf und sind von fundamentalem Interesse in der Mehrkörperquantenphysik. Es wird erwartet, dass sie in der Zukunft auch eine wichtige Rolle für die Entwicklung von Quantencomputern spielen werden.

In letzter Zeit wurden einige Materialien entdeckt, welche diese frustrierten Anordnungen aufweisen und einzigartige, ungewöhnliche Eigenschaften in Aussicht stellen. Mit diesem Projekt werden wir einen Schritt weiter gehen. Wir werden einige dieser neu entdeckten magnetische Systeme modifizieren, um so Kontrolle über ihre Eigenschaften zu erlangen. Externe Störgrössen wie zum Beispiel magnetische Felder, hydrostatischer Druck oder chemische Substitution werden dabei zur Anwendung kommen. Sie dienen dazu, die Materialien zwischen einem magnetisch geordneten Zustand und dem als Quantenspinflüssigkeit bekannten Zustand hin und her zu schalten. Dabei werden wir mit Hilfe einer Reihe mikroskopischer Techniken die verschiedenen Grundzustände und Zustandsübergänge untersuchen.

Direct link to Lay Summary Last update: 29.03.2018

Responsible applicant and co-applicants

Publications

Publication
Persistent spin dynamics in the pressurized spin-liquid candidate YbMgGaO4
Majumder Mayukh, Simutis Gediminas, Collings Ines E., Orain Jean-Christophe, Dey Tusharkanti, Li Yuesheng, Gegenwart Philipp, Tsirlin Alexander A. (2020), Persistent spin dynamics in the pressurized spin-liquid candidate YbMgGaO4, in Physical Review Research, 2(2), 023191-023191.

Collaboration

Group / person Country
Types of collaboration
Takagi group, Max Planck Institute for Solid State Research Stuttgart Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
ANR LINK meeting Talk given at a conference NMR study of Na3Ir3O8:What happens to magnetism in a doped spin liquid on a hyperkagome lattice 10.04.2020 Orsay (Zoom conference), France Simutis Gediminas;
Karlsruher Institut für Technologie, Institute for Quantum Materials and Technologies seminar Individual talk Tuning quantum magnets 18.02.2020 Karlsruhe, Germany Simutis Gediminas;
Strongly correlated electron systems conference, Okayama Talk given at a conference NMR study of a doped hyperkagome Na3Ir3O8 23.09.2019 Okayama, Japan Simutis Gediminas;
University of Zurich Condensed Matter Seminar Individual talk Tuning quantum magnets: Perturb to reveal 11.09.2019 Zurich, Switzerland Simutis Gediminas;
Nordic Neutron Scattering school 2018 Talk given at a conference Lattice vibrations and inelastic neutron scattering 09.09.2019 Tartu, Estonia Simutis Gediminas;
ANR Socrates meeting Talk given at a conference NMR study of Na3Ir3O8:ideas, preliminary results and open questions 22.05.2019 Orsay, France Simutis Gediminas;
General seminar for PhDs and Postdocs at LPS Individual talk Why do we care about high pressure? 23.03.2019 Orsay, France Simutis Gediminas;


Associated projects

Number Title Start Funding scheme
149486 Interplay between the superconductivity and magnetism in cuprate and Fe-based superconductors 01.08.2014 Project funding (Div. I-III)

Abstract

Magnetic insulators host many physical phenomena from the emblematic field of phase transitions to ordering in complex magnetic structures. In some cases, however, the magnetic order can be destabilized by quantum fluctuations leading to a spin-liquid state with exotic excitations. This has been demonstrated in one dimension but up until recently has remained enigmatic in higher dimensions. Spin liquid state in higher dimensions requires introducing frustration, which prevents a microscopic minimization of interactions between spins. This has long been a realm of theoreticians, but over the last decade some good realizations of frustrated lattices have been discovered and the experimental field is now expanding rapidly. Most notably, the structurally perfect quantum kagome material herbertsmithite (ZnCu3(OH)6Cl2) has been studied extensively. While many physics questions remain, the material issues by now have been mainly solved. This puts us in a perfect position to carry out a dedicated physics research program, studying the effects of perturbation on the ground state and excitations of such systems. Therefore, the objective of the proposed project is to intentionally perturb frustrated magnetic systems and explore the resulting effects which provide information about the unperturbed host system. Such a “perturb too reveal” approach has proven very efficient in other contexts such as one-dimensional antiferromagnetically correlated systems and high temperature superconductors but up until now has been not employed in the context of highly frustrated magnets. The model materials to be studied include the aforementioned herbertsmithite as well as a family of iridate materials where a 3D hyperkagome lattice is realized with emergent phenomena due to strong spin-orbit coupling. The weak Mott insulator in iridate will be pushed into metallic state and the effect on magnetism will be studied. The systems will be perturbed in three ways - substituting with other elements, applying magnetic field and hydrostatic pressure. The effect on the physical properties will be studied using two complementary methods: Nuclear Magnetic Resonance (NMR) and Muon Spin Rotation (muSR) techniques.The project will be carried out in the laboratory of one of the world leaders in the field of frustrated magnetism. The in-house experimental expertise of NMR and muSR techniques will be complemented by the collaborations with theoretical physicists and solid-state chemists. A well-rounded support will enable me to make use of my experience of defects in low-dimensional systems (PhD) and to apply my knowledge of high-pressure muon techniques (post-doc) in order to study the perturbations in frustrated magnets.I will tackle the question of the nature of spin liquids in two and three dimensions. Many problems remain unsolved, including the understanding of the ground state in some model lattices. Additionally, my approach will allow studying impurity-induced effects as well as different quantum phase transitions. A particularly enticing part of the project is to look for the spin textures around the defects, which are bound to show specific features in frustrated magnets. Finally, the study of the iridate hyperkagomes will shed the light on the interplay between charge and spin of the electrons. The proposed project will solidify the understanding of spin liquids and open new avenues of future research.
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