2006/09/07 by Sylvain Capponi, S. Capponi, Fakher F. Assaad +1
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Context (archaeology) #Electron #Fermi liquid theory #Liquid crystal #Phase (matter) #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Quantum spin liquid #Spin (aerodynamics) #Spin polarization #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.75.045115
published as Phys. Rev. B 75, 045115 (2007) · 9 pages, 19 figures. Problem with figures has been fixed
arxiv created 2006/09/07 · openalex publication_date 2007/01/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Strongly interacting systems are known to often spontaneously develop exotic ground states under certain conditions. For instance, spin nematic phases have been discovered in various magnetic models. Such phases, which break spin symmetry but have no net local magnetization, have also been proposed by Nersesyan et al. [J. Phys.: Condens. Matter 3, 3353 (1991)] in the context of electronic models. We introduce a N-flavor microscopic model that interpolates from the large-N limit, where mean field is valid and such a nematic phase occurs, to the more realistic N=1 case. By using a sign-free quantum Monte Carlo, we show the existence of a spin nematic phase (analogous to a spin flux phase) for finite N; when N decreases, quantum fluctuations increase and this phase ultimately disappears in favor of an s-wave superconducting state. We also show that this nematic phase extends up to a finite critical charge doping. Dynamical studies allow us to clarify the Fermi surface property: in the nematic phase at half-filling, it consists of four points and the low-energy structure has a Dirac conelike shape. Under doping, we observe clear signatures of Fermi pockets around these points. This is one of the few examples where numerical simulations show how quantum fluctuations can destroy a large-N phase.