Campus Units

Materials Science and Engineering, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

9-15-2014

Journal or Book Title

Physical Review B

Volume

90

Issue

11

First Page

115407

DOI

10.1103/PhysRevB.90.115407

Abstract

We study the unoccupied region of the electronic structure of the fivefold symmetric surface of an icosahedral (i) Al-Pd-Mn quasicrystal. A feature that exhibits parabolic dispersion with an effective mass of (1.15±0.1)me and tracks the change in the work function is assigned to an image potential resonance because our density functional calculation shows an absence of band gap in the respective energy region. We show that Sn grows pseudomorphically on i−Al−Pd−Mn as predicted by density functional theory calculations, and the energy of the image potential resonance tracks the change in the work function with Sn coverage. The image potential resonance appears much weaker in the spectrum from the related crystalline Al-Pd-Mn surface, demonstrating that its strength is related to the compatibility of the quasiperiodic wave functions in i−Al−Pd−Mn with the free-electron-like image potential states. Our investigation of the energy region immediately above EF provides unambiguous evidence for the presence of a pseudogap, in agreement with our density functional theory calculations.

Comments

This article is published as Maniraj, M., Abhishek Rai, S. R. Barman, M. Krajčí, Deborah L. Schlagel, Thomas A. Lograsso, and Karsten Horn. "Unoccupied electronic states of icosahedral Al-Pd-Mn quasicrystals: Evidence of image potential resonance and pseudogap." Physical Review B 90, no. 11 (2014): 115407. DOI: 10.1103/PhysRevB.90.115407. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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