arXiv subjects
Publications and source records attributed to G. Baskaran.
We study the perturbative correction to the ground state energy eigenvalue of a 2-dimensional dilute fermi gas with weak short-range two body repulsion. From the structure of the energy shift we infer the presence of an induced two body long range repulsive interaction $ {\displaystyle {1\over{r^2}} }$ among the constituent electrons indicating a potential instability of the fermi liquid ground state.
We extend the correlated electron model of Baskaran [Mod. Phys. Lett. {\bf B5}, 643(1991)] to the case of coupled layers. We show that the nature of the non-Fermi liquid ground state leads to the absence of electron-like quasiparticles at the Fermi surface, thereby suppressing coherent transport of electrons between the coupled layers (``confinement''). On the other hand, motion of singlet pairs between the layers is not blocked. We also discuss how pair tunneling can be used to construct a superconducting ground state.
We present physical arguments as well as numerical evidence to show that the Cooper pair (gap) function vanishes on the Fermi surface in strongly correlated electron systems such as \tJ and \lU Hubbard models in one and two dimensions. Using exact diagonalization, we study a correlation function which is a measure of the gap function even in a finite system, and present numerical results for this correlation function on small clusters of 8 (Hubbard) and 16 ($t-J$) sites.
We present results obtained (by exact diagonalization) for the problem of two t-J planes with an interlayer coupling $t_\perp$. Our results for small hole concentrations show that in-plane superconducting correlations are enhanced by $t_\perp$. When the constraint on double occupancy in the t-J model is relaxed, the enhancement disappears. These results illustrate the inter--layer tunneling mechanism for superconductivity.