Internal Spin Degrees Of Freedom Research Articles

Confined quantum systems in one dimension and conductance oscillations in narrow channels.

An exactly solvable electron model of a confined system with inverse-square interaction is presented. The ground state is given by the Jastrow-product wavefunction of power-law form. We discuss the results in connection with conductance oscillations observed in semiconductor nanostructures, for which single-electron charging effects play a crucial role. Due to the internal spin degrees of freedom, there appear two independent periods of the conductance oscillations in very narrow channels even at zero temperature.

Generalizing the t-J model: Triplet holes.

As a consequence of the local conservation of total spin in doped Mott-Hubbard insulators, the carriers may have an internal spin degree of freedom. We study the motion of an s=1 carrier in an s=1/2 background, finding that its propagation is quite different from that of the singlet holes of the t-J model: For a single hole, the tendency to form ferromagnetic polarons is suppressed and the single-hole spectral function in the two-dimensional Heisenberg antiferromagnet is completely incoherent.