Spin degree of freedom and tunneling through a quantum dot

A review is given on theoretical studies of roles of the spin degree of freedom in transport through a quantum dot with the total spin S for N electrons and S for N + 1 electrons in the ground state. The conductance and the phase coherency are expressed in terms of universal functions of S, (S) over tilde, and the spin splitting at small tunneling rates in the absence of spin-orbit interactions and are shown to exhibit the correlation between tunnelings of electrons with opposite spins and the dephasing due to spin flips.