STM: Al-Pd-Mn quasicrystal, 15x15 nm2
Root-mean-square roughness, W, as a function of annealing
temperature, for various surfaces based on STM images.
Note: Al-Pd-Zn and Al-Cu-Co are quasicrystals.
STM: Ag on top of Ag/Si(111) - (?3x?3)R30° at 250 K
STM: Au islands on NiAl(110) at 300 K, 150x150 nm2
STM: S reconstruction of Ag(100) after heating to 300 K, 100x100 nm2
LEED: clean NiAl(110)
More images with descriptions
165eV at 120 K
We try to understand real problems in corrosion, lubrication,
heterogeneous catalysis and microelectronics (thin films) by creating
simple model surfaces and studying their chemistry on an atomic scale.
We then extrapolate this information back to the real system, where
such knowledge is often unobtainable, either because of a lack of
adequate experimental techniques or because of misleading extraneous
factors. In order to create a simple model of a surface chemical
process, we use single crystal surfaces with known morphology.
Ultrahigh vacuum provides the well-controlled chemical environment
necessary to study a reactive surface over a period of several hours.
We can deliberately expose the sample to a chosen gas in order to
change its surface composition and then characterize it.
There are three major projects currently underway in my group. These
projects have all been selected because of their importance to
fundamental and applied surface chemistry, and also because they are
relatively new and unexplored. These projects involve:
We primarily use scanning tunneling microscopy (STM) and low-energy
electron diffraction (LEED) in our studies. Examples are shown to the
left and on the linked pages
New publication: "Cu2S3 complex on Cu(111) as a
candidate for mass transport enhancement"
was published January 22nd, 2015 by Physical Review B.
New publication: "The (111) Surface of NaAu2: Structure,
Composition, and Stability" was
published December 17th, 2014 by Inorganic Chemistry.
New publication: "Determining whether metals nucleate homogeneously
on graphite: A case study with copper"
was published November 5th, 2014 by Physical Review B.
Welcome to our newest group members, graduate students Ann
Lii and Peter Spurgeon who joined Nov. 2014!
New publication: "Transition metals on the (0001) surface of
graphite: Fundamental aspects of adsorption, diffusion, and
morphology" was published
September 2nd, 2014 by Progress in Surface Science.
Congratulations to David Appy for successfully
defending his Ph.D.! Thesis title: "Nucleation and growth of metals on
carbon surfaces". He will begin a Lecturer position at the end of
August for the Department of Chemistry at Iowa State University.
The Thiel group members are so very proud to congratulate Prof.
Thiel for being named the 2014 winner of the AVS Medard W.
Welch Award for "seminal contributions to the understanding of
quasicrystalline surfaces and thin-film nucleation and growth"! Please
refer to this news release from the Ames Laboratory.
New publication: "Search for the Structure of a Sulfur-Induced
Reconstruction on Cu(111)" was published August 7th, 2014 by
The Journal of Physical Chemistry C.
Congratulations to Emma Kwolek for winning a 2014
Teaching Excellence Award, and to Holly Walen for
winning a Dr. Ching Ching Chiu Fellowship for Women Doctoral Chemistry
Students! Both awards are from the Department of Chemistry at Iowa
New publication: "Structure of the clean Gd5Ge4(010)
surface" was published October 28th, 2013 by Journal of
Physics Condensed Matter.
New publication: "Analytic formulations for one-dimensional decay of
rectangular homoepitaxial islands during coarsening on anisotropic
fcc (110) surfaces" was published October 24th, 2013 by Physical
Congratulations to Dahai Shao for successfully
defending his Ph.D.! Thesis title: "Surface-Supported Ag Islands
Stabilized by a Quantum Size Effect: Their Interaction with Small
Molecules Relevant to Ethylene Epoxidation."
New publication: "Intermetallic NaAu2 as a heterogeneous
catalyst for low temperature CO oxidation" was published June
11, 2013 by Journal of the American Chemical Society.
New publication: "Growth
of fcc(111) Dy multi-height islands on 6H-SiC(0001) graphene"
was published May 15, 2013 by Journal of Physics: Condensed
New publication: "Anisotropic coarsening: One-dimensional decay of Ag
islands on Ag(110)" was published April 17, 2013 by Physical
New publication: "Communication: Structure, formation and
equilibration of ensembles of Ag-S complexes on an Ag surface"
was published February 15, 2013 by Journal of Chemical Physics.
New publication: "Surface Characterization of Clean Gd5Ge4(010)"
MRS Proceedings 1517 (2013).