Showing papers by "Hae-Young Kee published in 2003"
TL;DR: In this paper, a model for the electronic nematic phase on a square lattice with emphasis on the phase transition between isotropic and nematic phases within mean-field theory is presented.
Abstract: The electronic nematic phase occurs when the point-group symmetry of the lattice structure is broken, due to electron-electron interactions. We study a model for the nematic phase on a square lattice with emphasis on the phase transition between isotropic and nematic phases within mean-field theory. We find the transition to be first order, with dramatic changes in the Fermi-surface topology accompanying the transition. Furthermore, we study the conductivity tensor and Hall constant as probes of the nematic phase and its transition. The relevance of our findings to Hall resistivity experiments in the high-${T}_{c}$ cuprates is discussed.
61 citations
TL;DR: In this article, the precise meaning of a superconducting transition driven by kinetic as opposed to that driven by potential energy is discussed. But it is argued that this is a semantic question.
Abstract: Condensation energy in a superconductor cannot be precisely defined if mean-field theory fails to hold. This implies that in the case of high-temperature superconductors, discussions of quantitative measures of condensation energy must be scrutinized carefully because the normal state is anomalous and the applicability of a mean-field description can be questioned. A related issue discussed here is the precise meaning of a superconducting transition driven by kinetic as opposed to that driven by potential energy; we argue that this is a semantic question.
15 citations
TL;DR: In this paper, the Raman spectra of spin-triplet superconductors in Sr 2 RuO 4 were studied and the p-wave and f-wave symmetries were considered.
Abstract: We study the Raman spectra of spin-triplet superconductors in Sr 2 RuO 4 . The p-wave and f-wave symmetries are considered. We show that there is the clapping mode with frequency of √2Δ(T) and Δ(T) for p-wave and f-wave superconductors, respectively. This mode is visible as a huge resonance in the B 1 g and B 2 g modes of Raman spectra. We discuss the details of the Raman spectra in these superconducting states.
13 citations
TL;DR: In this article, the authors studied the longitudinal sound propagation in the electronic nematic Fermi liquid where theFermi surface is distorted due to the spontaneously broken rotational symmetry.
Abstract: Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada(Dated: February 1, 2008)We study the longitudinal sound propagation in the electronic nematic Fermi liquid where theFermi surface is distorted due to the spontaneously broken rotational symmetry. The behavior ofthe sound wave in the nematic ordered state is dramatically different from that in the isotropicFermi liquid. The collective modes associated with the fluctuations of the Fermi surface distortionin the nematic Fermi liquid leads to the strong and anisotropic damping of the sound wave. Therelevance of the nematic Fermi liquid in doped Mott insulator is discussed.
12 citations
TL;DR: In this paper, the effect of the four-particle ring exchange process on an orbital antiferromagnetic state in correlated electron systems in two dimensions has been studied and the phase diagrams in the large-$N$ mean field theory are obtained for half-filling and finite hole concentrations at zero temperature.
Abstract: We study the effect of four-particle ring exchange process on an orbital antiferromagnetic state that occurs in some correlated electron systems in two dimensions. The primary question is whether the ring exchange process enhances or suppresses the orbital antiferromagnetic ordering. Using the fact that the orbital antiferromagnetic state arises in the large-$N$ limit of the $\mathrm{SU}(N)$ generalization of the $t\ensuremath{-}J$ model, we consider the large-$N$ limit of the $t\ensuremath{-}J\ensuremath{-}K$ model where K represents the four-particle ring exchange term. The phase diagrams in the large-$N$ mean-field theory are obtained for the half-filling and finite hole concentrations at zero temperature. It is found that the ring exchange in general favors dimerized states or the inhomogeneous orbital antiferromagnetic state and suppresses the homogeneous orbital antiferromagnetic state. We compare our results with other related models of strongly correlated systems with ring exchange processes.
5 citations