• Séminaire théorie
• Personne à contacter : Adolfo Grushin ()
• location ROOM

Résumé : At strong repulsion, the triangular-lattice Hubbard model is described by S=1/2 spins with nearest-neighbor antiferromagnetic Heisenberg interactions and exhibits conventional 120° order. When decreasing the interaction, additional four-spin interactions are naturally generated from the underlying Mott-insulator physics of electrons. Although these interactions have historically been connected with a gapless ground state with emergent spinon Fermi surface (SFS), we find that at physically relevant parameters, they stabilize a chiral spin-liquid (CSL) of Kalmeyer-Laughlin (KL) type, clarifying observations in recent studies of the Hubbard model. We then present a self-consistent solution based on a mean-field rewriting of the interaction to obtain a Hamiltonian with similarities to the parent Hamiltonian of the KL state, providing a physical understanding for the origin of the CSL. Using a combination of the infinite density matrix renormalization group and exact diagonalization, we also study the wider phase diagram of the spin model, shedding light on the fate of the SFS state. Finally, we will comment on experimental systems in which triangular lattice Hubbard model physics might be observed. Ref.: Phys. Rev. Lett. 127, 087201 (2021).

• Séminaire nano-électronique quantique
• Personne à contacter :
• location ROOM

Résumé : One of the main directions to realize the topological quantum bit is combining topological materials with conventional superconductors. The notion of topological phases has been extended to higher-order and has been generalized to different dimensions. In the last few years, our research demonstrates the possibility of realizing the topological superconductivity in engineered 3D Dirac semimetals [1,2] and their 1D hinge states. Particularly, Cd3As2 is predicted to be a higher-order topological semimetal, possessing three-dimensional bulk Dirac fermions, two-dimensional Fermi arcs [3], and one-dimensional hinge states [4]. These topological states have different characteristic length scales in electronic transport, allowing one to distinguish their properties when changing sample size. [1] Li, C. et al. Nat. Mater. 17, 875–880 (2018). [2] Wang, A. Q. et al. Phys. Rev. Lett. 121, 237701 (2018). [3] Li, C.-Z. et al. Nat. Commun. 11, 1150 (2020). [4] Li, C.-Z. et al. Phys. Rev. Lett. 124, 156601 (2020).

Liens :[Twente University (NL)]

• Séminaire LPMMC
• Personne à contacter : Vincent Rossetto ()
• Conférence Zoom : consulter le lien de connexion dans les emails d'annonce ou contacter l'organisateur

• Personne à contacter : Vincent Rossetto ()
• Conférence Zoom : consulter le lien de connexion dans les emails d'annonce ou contacter l'organisateur

• Séminaire LPMMC
• Personne à contacter : Vincent Rossetto ()
• Conférence Zoom : consulter le lien de connexion dans les emails d'annonce ou contacter l'organisateur

• Séminaire LPMMC
• Personne à contacter : Denis Basko ()
• location ROOM

• Séminaire LPMMC
• Personne à contacter : Vincent Rossetto ()
• Conférence Zoom : consulter le lien de connexion dans les emails d'annonce ou contacter l'organisateur

• Séminaire LPMMC
• Personne à contacter : Vincent Rossetto ()
• Conférence Zoom : consulter le lien de connexion dans les emails d'annonce ou contacter l'organisateur

• Séminaire LPMMC
• Personne à contacter : Vincent Rossetto ()
• location ROOM