High-resolution photoemission from a tunable quantum well: Cu(111)/Na
Artikel i vetenskaplig tidskrift, 1997

High-resolution photoemission (ΔE=5 meV) at a low photon energy (3.82 eV) is used to probe discrete quantum-well-type subband states near, below, and above EF for Cu(111) covered with 2 ML or less of Na. A subband characteristic of the monolayer range shifts gradually to lower energy as the coverage is increased, extending below the Fermi level for coverages above 0.85 ML. Combined with previous observations of shifts for filled and empty states the present results show that the Na monolayer has continuously tunable quantum-well state energies. Beyond the monolayer range quantum-well states characteristic of both one and two atomic layers are observed, indicating growth of the second layer via monolayer high islands. A small downshift, by 25 meV, with increasing coverage in the second layer is ascribed to an increase of the island size. Lorentzian photoemission line shapes are observed for well-ordered samples. The linewidth varies linearly with temprature in the probed range (130–295 K) and this is ascribed to the phonon contribution to the width. Structural disorder leads to an asymmetric line, which is Lorentzian on the steeper, low-kinetic-energy side.

Författare

Anna K Carlsson

Chalmers, Teknisk fysik

Bo Hellsing

Chalmers, Teknisk fysik

Stig-Åke Lindgren

Chalmers, Teknisk fysik

Lars Erik Gustaf Wallden

Chalmers, Teknisk fysik

Physical Review B - Condensed Matter and Materials Physics

1098-0121 (ISSN)

Vol. 56 3 1593 - 1600

Ämneskategorier

Övrig annan teknik

DOI

10.1103/PhysRevB.56.1593

Mer information

Skapat

2017-10-08