Gapless ground state in the archetypal quantum kagome antiferromagnet ZnCu3(OH)6Cl2 - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Nature Physics Année : 2020

Gapless ground state in the archetypal quantum kagome antiferromagnet ZnCu3(OH)6Cl2

Résumé

Spin liquids are exotic phases of quantum matter challenging Landau's paradigm of symmetry-breaking phase transitions. Despite strong exchange interactions, spins do not order or freeze down to zero temperature. While well-established for 1D quantum antiferromagnets, in higher dimension where quantum fluctuations are less acute, realizing and understanding such states represent major issues, both theoretical and experimental. In this respect the simplest nearest-neighbor Heisenberg antiferromagnet Hamiltonian on the highly frustrated kagome lattice has proven to be a fascinating and inspiring model. The exact nature of its ground state remains elusive and the existence of a spin-gap is the first key-issue to be addressed to discriminate between the various classes of proposed spin liquids. Here, through low-temperature Nuclear Magnetic Resonance (NMR) contrast experiments on high quality single crystals, we single out the kagome susceptibility and the corresponding dynamics in the kagome archetype, the mineral herbertsmithite, ZnCu$_3$(OH)$_6$Cl$_2$. We firmly conclude that this material does not harbor any spin-gap, which restores a convergence with recent numerical results promoting a gapless Dirac spin liquid as the ground state of the Heisenberg kagome antiferromagnet.

Domaines

Matériaux

Dates et versions

hal-02624312 , version 1 (26-05-2020)

Identifiants

Citer

P. Khuntia, Matias Velázquez, Quentin Barthélemy, Fabrice Bert, Edwin Kermarrec, et al.. Gapless ground state in the archetypal quantum kagome antiferromagnet ZnCu3(OH)6Cl2. Nature Physics, 2020, 16 (4), pp.469-474. ⟨10.1038/s41567-020-0792-1⟩. ⟨hal-02624312⟩
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