Michael Matthew John
TREACY
Home Address: 140
West Courtney Lane, Phone:
(480) 598-9021
Tempe,
Arizona 85284-3911. email:
mike_treacy@mac.com
Date & Place of Birth: 13th
October 1954 Londonderry,
N. Ireland
Nationality: Naturalized
United States Citizen
Cambridge
University, St John’s College, U.K.
1980 Ph.D.
(Cavendish Laboratory). Thesis Title: “Electron Microscopy of Palladium and
Platinum Catalysts”. Supervisor, Dr. A. Howie.
1976 B.A.
Hons. 2.1 Natural Sciences (Theoretical and Experimental Physics).
Dissertation: “Dynamics of the Earth–Moon System”. Supervisor, Prof. A.
H. Cook.
St. John’s College, Southsea, U.K.
1971 10 ‘O’ levels (six grade 1 passes).
1973 3 ‘A’ levels (three
grade A passes), Distinctions in Physics and Mathematics.
6/2003–present Professor,
Dept of Physics & Astronomy
Arizona
State University, AZ, USA
10/1990–11/2002 Senior
Research Scientist
NEC
Research Institute, Inc., Princeton, N.J., USA
9/1984–10/1990 Staff
Physicist Exxon
Research & Engineering Co, Corporate Research, N.J., USA
9/1982–8/1984 Senior
Physicist
Exxon
Chemical Company, Aromatics Technology Division, N.J., USA
4/1981–8/1982 Ingénieur
(Grade II) Centre
National d’Etudes des Télécommunications, Bagneux, Paris
1/1980–3/1981 IBM
World Trade Post–Doctoral Position, IBM
Thomas J. Watson Research Center, Yorktown Heights, N.Y., USA
• Co–Organizer
of the Materials Research Society Symposium on “Microstructure and Properties of Catalysts” Editor Proceedings, Vol. No. 111. (12/1987)
• Meeting
Chair 1991 Materials Research Society Fall meeting, with M. Yoo (Oak Ridge)
& J. Phillips (Bell Labs).
• Treasurer,
program committee, Editor, 9th International Zeolite Conference, Montréal,
6/1992.
• Chairman
of the Structure Commission of the International Zeolite Association.
• Member
of the Council of the International Zeolite Association.
• Member
(retired) of the Steering Committee of the National Center for Electron
Microscopy (1989–1994).
• Treasurer,
Editor, for the 12th International Zeolite Conference, Baltimore, 6/1998.
• Meeting
Chair of Gordon Research Conference on “Zeolites and Layered Clays” 6/2002.
Wright Award 1974.
Awarded by St. John’s College Cambridge, for academic excellence.
Best Biological
Poster at the 1995 Microscopy Society of America conference (best out of
160).
Barrer Award 1990.
Awarded triennially by the Royal Society of Chemistry to a young scientist
under age 36, for distinguished work in the area of zeolites.
Donald W. Breck
Award 1996. Awarded triennially by the International Zeolite Association
for the most significant contribution to molecular sieve science and technology
during that 3-year period – for elucidating fault structures in FAU/EMT
zeolites.
• NSF GOALI grant DMR 00-74273,
co-Principal Investigator with P. J. Keblinski at Rensselaer Polytechnic,
supporting students R. Kishora-Dash and Juyin Cheng. “Structure
of Amorphous Materials by Fluctuation Microscopy and Atomic-level Simulation”.
$240,000
• Proposed,
and demonstrated, the high-angle annular detector for STEM Z contrast
My
Ph.D. work was on the development of advanced TEM-based techniques for the characterization
of supported Pt and Pd catalysts. At that time, Crewe’s Z contrast technique
seemed ideal for detecting high atomic number (Z) elements such as Pt,
on low atomic number supports that are typical of supported catalysts. I
demonstrated that diffraction produced stronger contrast that overwhelmed the Z-contrast effect in
crystals. In collaboration with supervisors A. Howie and L. M. Brown, I showed
that upon increasing the annular detector inner collection angle, diffraction
contrast could be suppressed. Further, the Z-dependence of the
signal improved to Z2 because atomic screening effects are
diminished. (This seemingly simple experiment required time and some
considerable ingenuity to overcome design limitations in the early STEM
instruments.) In later work, I demonstrated single Pt atom sensitivity in
zeolites. I also showed that high angle annular dark field intensities could be
used to estimate sub-nanometer particle sizes reliably. The high-angle annular
detector is now a standard tool in (S)TEM studies of materials.
• Identified
a new deactivation mechanism in Pt/K-zeolite L aromatization catalysts
My STEM Z
contrast studies of Pt particles in the one-dimensional channels of zeolite L
revealed that Pt particles agglomerate slowly with reaction time. The particles
remain sufficiently small that over 90% of the Pt atoms reside on particle
surfaces. However, double-blockages in the zeolite channels effectively entomb
a significant channel volume, and the loss of active Pt can be severe. I proposed
a length-loading criterion for maintaining activity. The criterion is simple:
there should not be enough Pt per channel to form two or more significant
blockages. This hypothesis was confirmed when zeolite L supports with shorter
channel lengths, but identical Pt loading, were tested. For proprietary reasons
this work (1982–1985), which represents the culmination of my early Z
contrast work, was published only in 1999. I won the prestigious Barrer Award
(awarded triennially by the British Zeolite Association) in 1990 for part of
this work.
• Demonstrated the
dominant role of elastic relaxation in TEM images of composition-modulated
films
My work at CNET in Paris was on spinodal
decomposition of InGaAsP semi-conductors, which are used as photodiodes in
fiber-optic telecommunications. Electron microscopy revealed pronounced
quasi-periodic image contrasts that were traditionally ascribed to local
composition fluctuations. In collaboration with J. M. Gibson and A. Howie, I
showed that the contrast is primarily due to the bending of lattice planes near
surfaces, which is induced by relaxation of stresses arising from the
modulation in unit cell dimensions. Such bending produces strong diffraction
contrasts. I derived equations for the bending, which remain useful for studies
of strain modulation in all types of modulated thin films, from superlattices
to ferroelectrics. This work also showed how to convert TEM lattice spacings
into a local composition, allowing for the relaxed tetragonal distortions and
their dependence on thickness.
• Unraveled
the structure of chiral zeolite beta
Synthetic zeolite beta was first reported
by Mobil in the mid 1960s. Its structure remained a mystery for over 20 years.
The presence of planar faults in the sub-micron sized crystallites made it
essentially impossible to solve the structure by conventional
structure-refining methods. Using TEM to extract structure projections and the
symmetry elements, in collaboration with J. M. Newsam, I showed that the
structure comprises intimately intergrown right- and left-handed variants of a
chiral tetragonal framework. (It later transpired that J. B. Higgins at Mobil
had solved the structure 3 years earlier by model-building, but had not been
allowed to publish.) The zeolite beta structure is important because it is a
3-dimensional 12-ring framework, with helical channels running along the
c-axis. Nobody has synthesized the pure right- or left-handed forms yet, but
such a pure end-member structure may have applications in chiral separations.
The methods I used, and the tools I created, in this work have been used by
other researchers for structure determinations of other intergrown zeolite
families.
• Invented
recursion algorithm for computing diffraction from faulted crystals –
DIFFaX
During
the course of the zeolite beta work, I developed a recursion method of
computing powder x-ray diffraction patterns in the presence of planar faults.
This tool helped provide the crucial evidence supporting our model of zeolite
beta. I am the primary author of the computer program DIFFaX, which has now become a
standard tool for simulation of diffraction in planar-faulted crystals, and has
been used widely by other researchers for over 10 years. I have used it
successfully in many projects to identify fault patterns in layered crystal
systems. The Fortran DIFFaX source code, with
manual, is in the public domain.
• Characterization of stacking fault patterns in faujasitic
zeolites using TEM and DIFFaX simulations
The tools I developed
for studying zeolite beta where applied to studying the faulting distributions
in the various faujasite-related synthetic zeolites, ranging from pure cubic
FAU framework to the pure hexagonal EMT framework. Using TEM and DIFFaX, I
showed that the faulting in these materials is clustered. Using the strain
relaxation model, I showed that the strains associated with the stacking faults
were reduced when faults were clustered. I won the prestigious Breck Award
(awarded triennially by the International Zeolite Association) in 1996 for this
work.
• Combinatorial computer
method for enumerating zeolite frameworks
In collaboration with
computer scientists K. Randall and S. Rao, I built a computer program to carry
out a combinatorial search over every possible crystallographic graph in order
to extract all of the 4-connected periodic zeolitic graphs. For one unique
tetrahedral atom there are over 6,400 4-connected graphs, of which about 200
refine to regular tetrahedral topology. This work took over 10 years to bring
to fruition, and discovered many new theoretical zeolite frameworks, and
revealed some interesting idiosyncrasies in the International Tables for
Crystallography. This work remains
active in a new collaboration with I. Rivin and E. Balkovski.
• Fluctuation
Microscopy: A powerful TEM technique for revealing medium-range order in
amorphous materials.
In collaboration with J.
M. Gibson, we have shown that statistical analysis of the speckle observed in
dark-field images of amorphous materials provides a measure of medium-range order.
We have called this new analytical TEM technique Fluctuation Microscopy.
We have used fluctuation
microscopy to solve some long-standing problems in amorphous materials. We have
shown that as-deposited amorphous germanium and silicon films contain paracrystalline
regions. On annealing below the recrystallization temperature, Ge (but not Si)
transforms to the lower-energy continuous random network. We have also shown
that amorphous hydrogenated silicon (a-Si:H) undergoes a significant structural
re-arrangement on light-soaking – an observation that may lead to an
improved understanding of the Staebler-Wronski effect which currently limits
the efficiency of a-Si:H solar cells. Fluctuation microscopy is now being used
in several laboratories. This work is in progress.
• Schläfli cluster methods for modeling amorphous tetrahedral models.
• In-situ TEM observations of domain switching in
ferroelectric thin films.
In collaboration with A. Krishnan, we
made in-situ TEM observations of domain wall motion in thin single crystal
ferroelectric materials under applied electric fields. I designed, and had
built, a special TEM specimen holder that can heat, apply electric fields and
shine light onto a sample. Our observations showed that domain walls do not
move as rigid membranes. Instead, we proposed that domain walls move by
allowing charged ripples to propagate along them. We developed a simple
Landau-Ginsburg Free energy argument showing that ripples have a reduced
barrier to switching. Ripples enable wall motion by a mechanism analogous to
that for dislocation motion in crystal slip. We also showed that some domain walls
are locked under certain electric field directions, representing an inherent
contribution to ferroelectric fatigue and imprint. This
work is still active.
When light is shone on a thin metallic
film, which has a periodic array of sub-optical wavelength diameter holes
drilled through it, anomalously high intensities are transmitted at certain
wavelengths. That is, more light gets through than would be expected from the
hole area. The current popular explanation is that surface plasmons “guide” the
light through the holes. I have developed an alternative dynamical diffraction
Bloch wave theory that completely explains the anomalous transmission, and does
so without resorting to special pleading about surface plasmons. The theory is
fully general for 3-dimensional periodic gratings, and unlike the other
theories, makes no simplifications or approximations to Maxwell’s equations.
This work is in progress.
• Exploited thermal
vibrations to measure Young’s modulus of carbon nanotubes
Long carbon nanotubes
that extend over holes in a TEM support film, cannot be imaged clearly at their
tips because of vibrations. The vibration amplitude at the tip can be several
nanometers, and this blurring motion is normally a problem for high-resolution
TEM studies. I realized that the vibrations are elastically relaxed phonons and
represent heat motion. By measuring the r.m.s. vibration amplitude as a
function of temperature, I estimated the Young’s modulus to be ~1.8 teraPascal,
which makes carbon nanotubes the stiffest known material. Later, in
collaboration with T. W. Ebbesen, A. Krishnan and E. DuJardin, we applied this
method to single-walled nanotubes and obtained values of 1.2 TPa, which we
believe are closer to the correct value. In collaboration with P. Yianilos, I
developed a hidden-parameter-inferencing technique to improve and quantify the
accuracy of the method. This unique application of TEM attracted international
attention, including highlights in Physics Today,
C&E News, New Scientist,
Bild der Wissenschaft etc…
• Designability of graphitic carbon cones.
In collaboration with Ebbesen, Krishnan
and DuJardin, we described in the journal Nature a special carbon black sample that
comprised a high density of graphitic disks and cones. Our TEM analysis
confirmed that the five topologically-allowed conical forms all occur, but with
a preponderance of the 60° cone-angle variety. I explain this distribution with
a simple model of graphitization. I point out that there are many more ways to
circumscribe carbon rings around the tip of a cone than there are ways to imbed
the same rings in planar graphite. For topologically flexible seeds, graphitic
cones are more “designable” than planar graphite. With an assumed seed
distribution, the model explains the observed cone distribution –
highlighting the role of entropy in the formation of curved graphitic structures.
Refereed
Journal Articles
(1) L. A. Freeman, A. Howie
and M. M. J. Treacy,
Bright Field and
Hollow-cone Dark-Field Electron Microscopy of Palladium and Platinum Catalysts,
J. Microsc., 111 165–178 (1977).
(2)
M. M. J. Treacy, A. Howie and C. J. Wilson,
Z Contrast of Platinum and Palladium Catalysts,
Philos. Mag., A38 569–585 (1978).
(3)
M. M. J. Treacy and A. Howie,
Contrast Effects in the Transmission Electron Microscopy of
Supported Crystalline Catalyst Particles
J. Catal., 63 265–269 (1980).
(4)
M.
M. J. Treacy, W. Krakow, D. A. Smith and G. Trafas,
A Technique For Comparing the Bulk and Surface Structure of Defects in Thin
Films Using the Scanning Transmission Electron Microscope,
Appl. Phys. Letts.,
38
341–345 (1981).
(5)
M.
M. J. Treacy,
Imaging With Rutherford Scattered Electrons in the STEM,
Scanning Electron Microsc., 1 185–197 (1981).
(6)
D.
A. Smith and M. M. J. Treacy,
Low-Loss Surface Imaging and Transmission Electron Microscopy of Growth of Some
Thin Films,
Applications of Surface Science, 11/12 131–143 (1982).
(7)
M.
M. J. Treacy,
Optimizing Atomic Number Contrast in Annular Dark Field Images of Thin Films in
the Scanning Transmission Electron Microscope,
J. Microsc. Spectrosc. Eléctron., 7 511–523, (1982).
(8)
F.
Glas, M. M. J. Treacy, M. Quillec and H. Launois,
Interface Spinodal Decomposition in LPE InGaAsP Lattice-Matched to InP,
J. de Physique,
43
C5 11–16 (1982).
(9)
C.
Colliex and M. M. J. Treacy,
Le Microscope Eléctronique à Balayage et en Transmission, ou STEM,
in Microscopie Eléctronique en Science des Materiaux, ed. by B. Jouffrey, A.
Bourret and C. Colliex, CNRS Publication (Paris) 391–424 (1983).
(10)
M.
M. J. Treacy and J. Bellessa,
On the Measurement of Surface Step Heights by Low-Loss Imaging in STEM,
Ultramicroscopy,
11
173–178 (1983).
(11)
M.
M. J. Treacy,
Atomic Number Imaging of Supported Catalyst Particles Using the Scanning
Transmission Electron Microscope,
in Catalytic Materials: Relationship Between Structure and Activity, ed. by T. E. Whyte, R.
A. Dalla Betta, E. G. Derouane and R. T. K. Baker, ACS Symposium Series No. 248 367–383 (1984).
(12)
J.
M. Gibson and M. M. J. Treacy,
The Effect of Elastic Relaxation on the Local Structure of Lattice-Modulated
Thin Films,
Ultramicroscopy,
14
345–350 (1984).
(13)
J.
M. Gibson, R. Hull, J. C. Bean and M. M. J. Treacy,
Elastic Relaxation in Transmission Electron Microscopy of Strained Layer
Superlattices,
Appl. Phys. Letts.,
46
649–651 (1985).
(14)