Correlated electron transport through a quantum dot: The multiple-level effect

Electron transport through a multilevel quantum dot with intradot Coulomb repulsion is discussed theoretically. Based on the calculated local density of states, we argue that characteristic peaks should be seen in differential conductance if the dot has a group of closely spaced levels. These peaks provide a hallmark of Kondo-type correlation. Our proposal is especially pertinent if one realizes that Kondo temperature in a multilevel system may be enhanced by orders of magnitude over that for a single-level system.