Seminars Archive

The properties of Be(10-10)

Abstract
Beryllium is a simple metal on the verge of being a semiconductor: the
electronic density of states has a minimum at the Fermi level and the
bonding is highly directional. The (0001) and (10-10) surfaces of Be still,
however, have a high local density of states at the Fermi level caused by
the presence of surface states. Hence, these surfaces may be viewed as a
model for quasi two-dimensional metals. The electronic structure of the two
Be surfaces is very different: while the closed packed (0001) surface
supports a free-electron like surface state, the electronic structure of
Be(10-10) consists of two electron pockets at the boundary of the surface
Brillouin zone which leads to strongly anisotropic screening.

In this talk measurements of the electronic, geometric and vibrational
structure of Be(10-10) are presented. The results are compared to recent
first-principles calculations [1] and discussed in the context of other
simple metal surfaces. An attempt is made to establish a connection between
the remarkable surface electronic structure and the other properties.

[1] R. Stumpf, private communication.