skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Herringbone and triangular patterns of dislocations in Ag, Au, and AgAu alloy films on Ru(0001).

Abstract

We have studied the dislocation structures that occur in films of Ag, Au, and Ag{sub 0.5}Au{sub 0.5} alloy on a Ru(0001) substrate. Monolayer (ML) films form herringbone phases while films two or more layers thick contain triangular patterns of dislocations. We use scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) to determine how the film composition affects the structure and periodicity of these ordered structures. One layer of Ag forms two different herringbone phases depending on the exact Ag coverage and temperature. Low-energy electron microscopy (LEEM) establishes that a reversible, first-order phase transition occurs between these two phases at a certain temperature. We critically compare our 1 ML Ag structures to conflicting results from an X-ray scattering study [H. Zajonz et al., Phys. Rev. B 67 (2003) 155417]. Unlike Ag, the herringbone phases of Au and AgAu alloy are independent of the exact film coverage. For two layer films in all three systems, none of the dislocations in the triangular networks thread into the second film layer. In all three systems, the in-plane atomic spacing of the second film layer is nearly the same as in the bulk. Film composition does, however, affect the details of the two layermore » structures. Ag and Au films form interconnected networks of dislocations, which we refer to as 'trigons.' In 2 ML AgAu alloy, the dislocations form a different triangular network that shares features of both trigon and moire structures. Yet another well-ordered structure, with square symmetry, forms at the boundaries of translational trigon domains in 2 ML Ag films but not in Au films.« less

Authors:
; ; ;  [1]; ; ; ; ;
  1. (University of Minnesota, Minneapolis, MN)
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
USDOE
OSTI Identifier:
972445
Report Number(s):
SAND2008-6492J
TRN: US201006%%9
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proposed for publication in Surface Science.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SILVER; GOLD; SILVER ALLOYS; GOLD ALLOYS; DISLOCATIONS; PATTERN RECOGNITION; FILMS; SUBSTRATES; RUTHENIUM

Citation Formats

Thayer, Gayle Echo, de la Figuera, Juan, Bartelt, Norman Charles, Carter, C. Barrington, Hwang, R. Q., Thurmer, Konrad, Ling, W. L., Hamilton, John C., and McCarty, Kevin F. Herringbone and triangular patterns of dislocations in Ag, Au, and AgAu alloy films on Ru(0001).. United States: N. p., 2008. Web.
Thayer, Gayle Echo, de la Figuera, Juan, Bartelt, Norman Charles, Carter, C. Barrington, Hwang, R. Q., Thurmer, Konrad, Ling, W. L., Hamilton, John C., & McCarty, Kevin F. Herringbone and triangular patterns of dislocations in Ag, Au, and AgAu alloy films on Ru(0001).. United States.
Thayer, Gayle Echo, de la Figuera, Juan, Bartelt, Norman Charles, Carter, C. Barrington, Hwang, R. Q., Thurmer, Konrad, Ling, W. L., Hamilton, John C., and McCarty, Kevin F. Wed . "Herringbone and triangular patterns of dislocations in Ag, Au, and AgAu alloy films on Ru(0001).". United States.
@article{osti_972445,
title = {Herringbone and triangular patterns of dislocations in Ag, Au, and AgAu alloy films on Ru(0001).},
author = {Thayer, Gayle Echo and de la Figuera, Juan and Bartelt, Norman Charles and Carter, C. Barrington and Hwang, R. Q. and Thurmer, Konrad and Ling, W. L. and Hamilton, John C. and McCarty, Kevin F.},
abstractNote = {We have studied the dislocation structures that occur in films of Ag, Au, and Ag{sub 0.5}Au{sub 0.5} alloy on a Ru(0001) substrate. Monolayer (ML) films form herringbone phases while films two or more layers thick contain triangular patterns of dislocations. We use scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) to determine how the film composition affects the structure and periodicity of these ordered structures. One layer of Ag forms two different herringbone phases depending on the exact Ag coverage and temperature. Low-energy electron microscopy (LEEM) establishes that a reversible, first-order phase transition occurs between these two phases at a certain temperature. We critically compare our 1 ML Ag structures to conflicting results from an X-ray scattering study [H. Zajonz et al., Phys. Rev. B 67 (2003) 155417]. Unlike Ag, the herringbone phases of Au and AgAu alloy are independent of the exact film coverage. For two layer films in all three systems, none of the dislocations in the triangular networks thread into the second film layer. In all three systems, the in-plane atomic spacing of the second film layer is nearly the same as in the bulk. Film composition does, however, affect the details of the two layer structures. Ag and Au films form interconnected networks of dislocations, which we refer to as 'trigons.' In 2 ML AgAu alloy, the dislocations form a different triangular network that shares features of both trigon and moire structures. Yet another well-ordered structure, with square symmetry, forms at the boundaries of translational trigon domains in 2 ML Ag films but not in Au films.},
doi = {},
journal = {Proposed for publication in Surface Science.},
number = ,
volume = ,
place = {United States},
year = {Wed Oct 01 00:00:00 EDT 2008},
month = {Wed Oct 01 00:00:00 EDT 2008}
}