Bound states in two-dimensional shielded potentials

Nagy, I.; Puska, M. J.; Zabala, N.

Bound states in two-dimensional shielded potentials

Authors

Nagy, I.

Puska, M. J.

Zabala, N.

Description

We study numerically the existence and character of bound states for positive and negative point charges shielded by the response of a two-dimensional homogeneous electron gas. The problem is related to many physical situations and has recently arisen in experiments for impurities on metal surfaces with Schockley surface states. Mathematical theorems ascertain a bound state for two-dimensional circularly symmetric potentials $V(r)$ with $\int_{0}^{\infty}{dr r V(r)} \leq 0$. We find that a shielded potential with $\int_{0}^{\infty}{dr r V(r)} > 0$ may also sustain a bound state. Moreover, on the same footing we study the electron-electron interactions in the two-dimensional electron gas finding a bound state with an energy minimum for a certain electron gas density.
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