Blanc SIMI 4 - Blanc - SIMI 4 - Physique des milieux condensés et dilués

Frustrated Spin Liquids – SpinLiq

Submission summary

Our project aims at a study of frustration induced two-dimensional quantum spin liquids. In the past years, the field has been spectacularly revived by the unprecedented discovery of a large number of experimental candidates, not only in triangular-based corner sharing lattices, like the famous kagome lattice, but also in edge sharing triangular lattices which come as a challenge to the commonly admitted Néel ground state. The nature of the ground state and of fractional excitations remains one of the most enduring problems in condensed matter physics both on experimental and theory sides. Further significant progress in the field now requires to master all the steps of the studies from synthesis to theory. Our project gathers knowledgeable scientists in all the fields with complementary skills, Institut des Matériaux de Nantes and Institut de Chimie de la Matière Condensée de Bordeaux, for materials synthesis and single crystal growth, the NMR-µSR Orsay team and B. Fak (SPSMS-CENG Grenoble), for inelastic neutron scattering, coupled to the theory team from LPTMC, Paris.
Tracking the ground state properties will require a number of subKelvin techniques, thermodynamic measurements, local susceptibility and relaxation measurements (NMR, µSR), inelastic neutron scattering which will enable us to probe the ultimate low-T the susceptibility and dynamics on various time scales. These quantities will be calculated by setting up a realistic Hamiltonian based on experimental results, including exchange interactions beyond 1st neighbours, cyclic exchange,… We will explore the possibility of field induced transitions and will probe the ground state through an original “pertub to reveal” approach benefitting from the local character of NMR which provides a map of spin textures induced by spin vacancies in these frustrated lattices. Such textures have been recently the subject of theoretical approaches.
The synthesis of 17O enriched single crystals for NMR of the first quantum kagome spin liquid, Herbertsmithite, ZnCu3(OH)6Cl2, the synthesis of the KCrO2 model Heisenberg triangular lattice compound represent worldwide synthesis challenges in the field of frustrated magnetism. The novel Mott insulator triangular, Ba3MSb2O9 (M=Cu, Ni, Co) family, besides their spin liquid character, have a strong potential since one can vary the magnetic ions and introduce non-magnetic defects (Zn, Mg) in a controlled manner. Finally through well-established international collaborations, we will study Haydeite [Colman, 2010] and a new vanadium-based kagome spin liquid compound [Aidoudi, 2011].
On the theory side, spin liquids have been quite speculative in the 70’s while more recently, in the 90’s, various spin liquid ground states have been predicted for model hamiltonians. Today, some materials exhibit such spin liquid behavior, we aim at understanding their nature, their excitations and compare directly to experimental quantities uncovered through the proposed studies in this project. There are numerous tracks to be explored, nature of fractionalized quasi-particles, of their interactions, impact of disorder…

Project coordination

Philippe MENDELS (Organisme de recherche)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

ICMCB Institut de chimie de la matière condensée de Bordeaux
IMN Institut des matériaux de Nantes
LPTMC Laboratoire de Physique Théorique de la Matière Condensée

Help of the ANR 537,880 euros
Beginning and duration of the scientific project: January 2013 - 36 Months

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