Quantitative LEED analysis of the surface structure of a MgCl2thin film grown on Pd(111)

Journal Article · Fri Aug 01 04:00:00 EDT 1997 · Surface Science

OSTI ID:899780

Roberts, J G; Gierer, M; Fairbrother, D H; Van Hove, M A; Somorjai, G A

An epitaxial, ultrathin single-crystal film (12 Angstrom) of MgCl[2] was deposited molecularly onto a Pd single crystal of (111) orientation at a crystal temperature of {approx}650 K. A detailed surface structure determination of this insulating film was performed by low-energy electron diffraction (LEED). A low incident LEED beam current (0.36 mu A) was employed to minimize the electron-stimulated desorption (ESD) of Cl. The best-fit model for the observed hexagonal MgCl[2](1 x 1) pattern corresponds to the unreconstructed (0001) Cl-terminated plane of alpha-MgCl[2], whose stacking sequence is Cl-Mg-Cl-Cl-Mg-Cl..., with a Pendry R-factor of 0.317. Small relaxations of the surface were found as 0.03 +- 0.03, 0,003 +-0.04 and 0.04 +- 0.08 Angstrom expansions of the first three Mg-Cl interlayer spacings, respectively, and a 0.10 +- 0.06 A contraction of the first Cl-Cl interlayer spacing. These small deviations were probably driven by the loss of the van der Waals interaction at the termination plane, since surface structure data for transition-metal dichalcogenides, which have different intralayer bonding, but the same intertrilayer bonding, report a similar magnitude of interlayer spacing deviations as seen in MgCl[2].

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Energy Research
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 899780
• Report Number(s): LBNL--40712
• Journal Information: Surface Science, Journal Name: Surface Science Journal Issue: 1 Vol. 399; ISSN SUSCAS; ISSN 0039-6028
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL STRUCTURE
DEPOSITION
ELECTRON DIFFRACTION
MAGNESIUM CHLORIDES
MATHEMATICAL MODELS
MONOCRYSTALS
PALLADIUM
SUBSTRATES
THIN FILMS