Quentin Barthélémy (Laboratoire National des Champs Magnétiques Intenses, Grenoble)
Titre : Identification of quantum spin liquids through coupling of their fractionalized excitations to acoustic phonons
Institut Néel, Salle E424 (Salle Louis Weil)
Résumé : Quantum spin liquids are long sought exotic states of matter, ubiquitous in one-dimensional systems and much scarcer in higher dimensions, with a possible connection to the problem of high-temperature superconductivity [1] and potential applications in the field of quantum information [2]. Falling beyond Landau’s paradigm of phase transitions, they are characterized by an absence of magnetic order or spin freezing down to 𝑇 = 0, macroscopic entanglement and emergent fractionalized excitations [3]. After introducing the quest for such states in dimension 𝑑 = 2, through the kagome and Kitaev routes, I will explain why ultrasound measurements (velocity, attenuation, Hall viscosity) are promising for uncovering their distinctive features [4]. More specifically, I will discuss our recent results obtained on the kagome candidate Y3Cu9(OH)19Cl8 and on the Kitaev candidate 𝛼-RuCl3.
[1] Anderson, Science 235, 4794, 1196-1198 (1987)
[2] Kitaev, Annals of Physics 321, 1, 2-111 (2006)
[3] Savary et al., Rep. Prog. Phys. 80, 016502 (2016)
[4] Serbyn et al., Phys. Rev. B 87, 174424 (2013) / Ye et al., Phys. Rev. Research 2, 033180 (2020)
