arXiv subjects
Publications and source records attributed to Hyun C. Lee.
The electronic Raman scattering of Borocarbide superconductors is studied based on the weak coupling theory with $s+g$-wave gap symmetry. The low energy behaviors and the relative peak positions can be naturally understood, while the explanation of the detailed shape of the $B_{1g}$ peak seems to require a strong inelastic interaction not present in the weak coupling theory.
Resonant Raman scattering of degenerate interacting two-channel quantum wire is studied. {\it All} collective excitations of two-channel quantum wire are shown to give rise to peaks in the polarized Raman spectra near resonance. If there exist certain symmetries among interactions, a resonant peak can also appear in the {\it depolarized} Raman spectra, in constrast to the single-channel case studied by Sassetti and Kramer. We also calculate the explicit form of the scattering cross-section away from the peaks. The above features may be experimentally verified in armchair carbon nanotube systems.
We study a model of the quantum critical point of cuprates associated with the "circulating current" order parameter proposed by Varma. An effective action of the order parameter in the quantum disordered phase is derived using functional integral method, and the physical properties of the normal state are studied based on the action. The results derived within the ladder approximation indicate that the system is like Fermi liquid near the quantum critical point and in disordered regime up to minor corrections. This implies that the suggested marginal Fermi liquid behavior induced by the circulating current fluctuations will come in from beyond the ladder diagrams.
Two one-dimensional Luttinger liquid systems coupled by Hund's coupling are studied by the renormalization group and the non-abelian bosonization methods. It is found that the Hund's coupling is always relevant irrespective of the repulsive interaction between electrons within each chain. The properties of the resulting strong coupling fixed point are discussed.