Comments
on some papers by Laszlo Mihaly and
co-workers
These comments were prepared in May/June, 2004. The numbers
refer to my list of publications. The
works are divided into groups rather arbitrarily, according to the
subject
matter and the location of the principal research effort. The papers
explicitly
cited here are somewhat more important to me than the rest, either
because they
attracted lots of attention, or because I am particularly fond of them.
--lm
1.
Early works (1976-83; 11 papers, 148 citations)
4 L.
Mihály and J. Sólyom
Renormalization Group Treatment of 3
dimensional ordering in a system of weakly coupled linear chains
J.
Low Temp. Phys. 24, 579 (1976) (1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18
)
6 L.
Mihály and A Zawadowski
Fermi Liquid Theory of the Degenerate
J.
Physique
Lettres 39,
483 (1979) (
1,
2,
3,
4,
)
As
a graduate student at the Central Research Institute for Physics,
I did the next heavy-duty calculation with
Fred Zawadowski [6]. I
was most astonished when a speaker at a Stony Brook seminar cited this
work in
2002; he had no idea that one of the authors was in the audience, and
he
clearly knew more about the content of the paper than I remembered. This paper has been cited several times
lately,
once in a Phys. Rev. Letters. Not bad
for a 24 years old publication!
10 L.
Mihály, S. Pekker
and A. Jánossy
NMR Investigation of the Structure of Pure
and Iodine Doped Polyacetilene
Synthetic
Metals, 1, 349 (1980)
12
H. Alloul and L.
Mihaly
Ti NMR Study of the Nearly Ferromagnetic
System TiBe2
Phys.
Rev.
Letters 48, 1420 (1983)
I
learned the basics on ESR and NMR from Andras
Janossy. The
work
published in [10] was our attempt to find out where the iodine goes
when polyacetylene, (CH)x,
is
doped. Later I spent two years in Orsay, working with Henri Alloul
[12].
He gave me lots of freedom; in
retrospect, I feel I could have done a bunch of interesting experiments
on charge
density wave systems, but missed the opportunity.
2. Charge
Density Waves,
13
Gy.
Hutiray, G. Mihály
and L. Mihály
Metastable
electronic states in orthorhombic TaS3
20 G.
Mihály and L. Mihály
Spontaneous Decay of Metastable
States in Orthorhombic TaS3
Phys.
Rev.
Letters 52, 149 (1984)
25 L. Mihaly, G.
Mihaly, A. Janossy
Remanent deformation
of CDWs
Lecture
Notes in Physics 217, 404 (1985) (
1,
2,
3,
4,
5,
6,
7,
8
)
In
1983 we discovered that the charge density waves (CDW) have all kinds
of metastable states, generated either by
electric field, or by
heat treatment. The CDW system seemed to
“remember” the direction of the last electric field pulse; we called
this the “Pulse
Sign Memory” effect. Also, precision
measurements of the resistivity revealed a
hysteresis in the temperature dependence of
the resistivity. In
[13]
we show that the two effects are intimately related.
(J.C. Gill in
Together with my brother George, we developed
a simple
picture. Imagine the CDW being a charged, heavy classical spring,
laying
straight on a flat horizontal surface with non-zero, random friction. If the string is pulled horizontally along its
length (with a strong electric force, but not strong enough to overcome
the
friction everywhere) it gets deformed, and remains in a deformed state
due to
the friction. A non-zero electric dipole
moment (polarization) can be created this way.
The thermally excited conduction electrons shield any static
polarization in the CDW system, but the transient processes are easily
observable. The final ingredient: the activation energy of the conduction
electrons, and therefore the resistivity
of the whole
sample, should be sensitive to the stressed state of the CDW. The details of the model were best explained
in [25]. It was amazing to see how well
the model predicted the results of the next experiment!
The proof of the pudding: in [20] we showed
that the relaxation of these metastable
states
exhibits the universal characteristics of randomly pinned systems.
22
L. Mihaly and A. Janossy
Current induced remanent
polarization of the CDW
What
is the length scale of the deformations?
We took the spring model of the CDW to the extreme, and
suggested that
the coherence extends all over the sample. If
that was true, an electric field pulse
could actually pile up the CDW to one side of the sample, resulting in
a metastable macroscopic difference
between the “left” and
“right” sides. In order to study this
effect, I designed a special probe (called the “touching contact”) to
measure
the potential without disturbing the CDW.
Indeed, the low field resistances of the left and right sides of
the
sample permanently recorded the direction of the last sliding CDW
motion [22].
2. Charge
Density Waves, UCLA (26 papers, 384 citations)
31 S.E.
Brown
and L. Mihaly
Coherent Voltage Oscillations: Interface or
Bulk Phenomena?
Phys
Rev.
Letters 55, 742 (1985)
At
the time George Grüner
invited me to UCLA, there was a fierce debate about the relative
importance of impurities
and electrical contacts in the generation of the narrow band noise
characteristic of sliding CDWs. Rob Thorne (presently at Cornell) and others
were
arguing for contacts. The UCLA group, Phuan Ong
(currently at
39
L. Mihaly, M. Crommie and G. Gruner
The Dynamics of Partially Pinned Random
Systems
Europhysics Letters 4,
103 (1987)
(
1,
2,
3,
4,
5,
6
)
Mike
Crommie (currently at UC Berkeley) was an
undergraduate at UCLA when he worked with me on this problem for a few
months. We simulated the response of
randomly pinned CDWs in a simple model of
“bricks and
springs”, and we expected to see the stretched exponential, exp{-(t/t0)a}, time dependence observed in our
experiments. Some of these calculations
converged very
slowly (perhaps not a coincidence, when we are talking about stretched
exponentials). This was the time when
computers
started to move out of the laboratories, and every administrator in the
Department demanded a new IBM PC. We set
up the ultimate multi-processor-parallel-computing shop:
Friday afternoon we programmed each
secretary’s computer with the same program, but a different electric
field. By Monday morning we had the
complete field dependence of the relaxation process.
We started with one dimensional CDW chains,
but the
agreement with the experiment was only qualitative: we got the
stretched
exponential, but the value of a disagreed with the experiment.
We than extended the calculations to higher dimensions (coupled
chains), but we
obtained no better of a match. Instead we had something else: the
computation
showed that the exponent a is about ˝ in one dimension, 2/3 in two
dimensions, ľ
in three dimensions. Not surprisingly in
infinite dimensions (easy to simulate, hard to realize experimentally)
the
exponent is exactly 1. Why this
regularity? I still do not know, but
there must be a simple explanation.
42
L. Mihaly, Ki-Bong Lee and P. Stephens
X-ray Diffraction Study of the Metastable
CDW States
This
X-ray work with Peter Stephens was the final and direct proof of the
delicate
structural changes associated with metastable
CDW
states. It also got me a job at Stony
Brook two years later.
3. High
Tc
Superconductors,
48 I. Furo, A. Janossy,
L. Mihaly, P. Banki, I. Pocsik, I. Bakonyi, I. Heinmaa,
E. Joon and E. Lippmaa
Nuclear Quadrupole
and Nuclear Magnetic
Resonance of Copper
in the High T Superconductor YBaCuO
When
the high Tc superconductivity
was
discovered, we had two major goals in
4. High Tc
Superconductors, Stony Brook (1989-94; 27
papers, 898
citations)
67 L.
Forro,
G.L. Carr, G.P. Williams, D. Mandrus, L.
Mihaly
Far-infrared transmission study
of single
crystal Bi2Sr2CaCu2O8 superconductors
Phys.
Rev.
Letters, 65, 1941, (1990)
88. D. Mandrus, M.C. Martin, C. Kendziora,
D. Koller, L. Forro,L. Mihaly
No far infrared Spectroscopic Gap in Clean
and Dirty High Tc Superconductors
Phys.
Rev.
Letters 70, 2629 (1993)
I
arrived at the Stony Brook Physics Department in early 1989. Laszlo Forro came a few months later and he
stayed for one and a half years as a research associate in my
laboratory
(afterwards, he moved to Libero Zuppiroli’s
group in Lausanne, and he is now a full professor at the EPFL). Together with two graduate students (David Mandrus, currently at
Laszlo started out by preparing
incredibly thin BSCCO single crystals.
We used them to study infrared transmission with the help of Gwyn Williams (currently the Basic Research Program Manager at Jefferson Lab) at the National Synchrotron
Light
Source. At the time the IR community
could not agree whether a sharp, BCS type gap existed in these
materials. Everyone else was measuring
reflectivity, and
there the question was whether the reflectance was perfectly 100% or
somewhat
less. In our transmission measurements,
however, the baseline was zero, making the experiment much more
accurate. In
[67] we show that the sharp BCS gap can be safely excluded as a
possibility. This happened at the time
when the d-wave superconductivity was still very
much out of fashion; the paper generated lots of controversy, but
survived the test
of time. In [88] we show that it is not
possible to explain away the gap with the “clean limit” arguments
favored by
others.
70 D. Mandrus, L
Forro,
D. Koller
and
L. Mihaly
Giant tunneling anisotropy in the high T superconductor Bi2Sr2CaCu2O8
Nature
351, 460, (1991)
89 D. Mandrus, J. Hartge,
C. Kendziora, L. Mihaly and L. Forro
Gapless superconductivity in Bi2Sr2YxCa1-xCu2O8
Europhysics Letters 22,
199 (1993)
(
1,
2,
3,
4,
5,
6
)
90 J. Hartge, L. Forro, D. Mandrus,
M.C. Martin, C. Kendziora, L. Mihaly
Tunneling and infrared spectroscopy on high Tc superconductor
J.
Phys.
Chem. Solids 54, 1359 (1993)
(
1,
2,
3,
4,
5,
6,
7,
8,
9,
10
)
Tunneling
is another principal method in the study of superconductors. Here too, there was a school of thought
arguing that the gap is sharp and clearly visible.
In retrospect, all of the measurements
supporting that idea were wrong. We
developed a break junction technique that proved to by extremely useful
in
these materials, and we demonstrated that there is no sharp gap, and
the
tunneling density of states is linear at low bias voltages [70], [89]. The only mistake we made was not saying the
words
“d wave”…. The best
summary of our optical and tunneling
studies is given in [90]. The first
author, Jeff Hartge, did many of the
tunneling
measurements. He was an undergraduate
student, and he ended up as a happy high school physics teacher.
69 D. Mandrus, L. Forro, C. Kendziora,
L. Mihaly,
Two dimensional electron
localization in single crystals of Bi2Sr2YxCa1-xCu2O8
Phys.
Rev.
B (Rapid Commun.) 44,
2418 (1991)
92 L.
Mihaly,
C. Kendziora, J. Hartge,
D.
Mandrus, L. Forro
High pressure cell for Oxygen annealing at
elevated temperatures
Rev.
Sci. Inst. 64,
2397 (1993)
(
1,
2
)
97 X. Du, L. Mihaly, P.B. Allen
Wiedeman-Franz
law in Bi2Sr2CaCu2O8
Physica B 194-196,
1507 (1994)
(
1,
2
)
We
had a strong materials preparation effort, supplemented by electronic
[69] and
heat transport [97] studies. During one
of our trips to the JFK airport (Laszlo was already in
5.
Fullerenes (1992- 1998; 18 papers, 1479 citations)
72 P.W.
Stephens, L. Mihaly, P.L. Lee, R.L. Whetten,
S.M.
Huang, R. Kaner, F. Diederich,
K. Holczer
Structure of single phase,
superconducting KC60
Nature
351, 632 (1991)
(
1,
2,
3
)
75 P.W.
Stephens, D. Cox, J.W. Lauher, L. Mihaly,
J. Wiley,
P. Allemand, A. Hirsch, K. Holczer,
Q. Li, J. Thompson and F. Wudl
Lattice structure of the
fullerene ferromagnet
TDAE-C60
Nature
355, 331 (1992)
(
1,
2
)
The
collaboration with Karoly Holczer
(UCLA) and Peter Stephens (my colleague in Stony Brook) produced some
of the
most spectacular results. I recall working
with Peter in Brookhaven Lab and later sitting in my backyard figuring
out how
to put the 3 potassium atoms into the structure (it seems trivial now,
like
most good problems that have already been solved) [72].
We got more than 500 citations to this
paper. However, I feel that our
contribution to the advancement of science was quite minor – if we did
not do
it, Robert Fleming and friends at Lucent Technologies would have done
it within
a week or two. Finding the unit cell of TDAE-C60
no less rewarding [75].
95
S. Pekker, L.
Forro, L. Mihaly, A. Janossy
Orthorhombic A1C60: a
conducting linear alkali fulleride
polymer?
98 S. Pekker, A. Janossy,
L. Mihaly, O.
Chauvet, M. Carrard,
L.
Forro
Single crystalline (KC60 )x : a conducting linear alkali fulleride polymer
Science
265 1077 (1994)
(
1,
2
)
101 M.C.
Martin, D. Koller, X. Du,
P.W. Stephens, L. Mihaly
Insulating and conducting phases of RbC60
Phys.
Rev.
B (Rapid Comm.) 49, 10818 (1994)
The
sociological context of A1C60 was quite different
from
that of A3C60.
When we first suggested the existence of A1C60,
most people in the community believed that we were crazy.
The phase diagram of AxC60
had already been mapped by the best materials scientists, and there was
no
place for a stable A1C60 material. In fact, we
proved
that this material existed by using the X-ray data collected by Gyula Faigel and
co-workers [95]
[98]. More importantly, this material was
the first one in a series of compounds where fullerenes polymerized. In a coordinated X-ray and infrared study my
students Mike Martin (currently at Lawrence Berkeley Lab) and Dan Koller (currently with the National Radio
Astronomy
Observatory) demonstrated that this polymerization leads to dramatic
changes in
the electronic properties [101]. (A
similar, independent study was done by Laszlo Forro, using ESR as the
main
probe.)
96 M.C.
Martin, X. Du, J. Kwon, L. Mihaly
Observation and assignment of silent and
higher order vibrations in the IR transmission of C60
crystals
114 Cheol Ho, Choi, Miklos Kertesz
and Laszlo Mihaly
Vibrational Assignment of All 46
Fundamentals of C60 and C60
J. Phys. Chem. A 104, 102-112
(2000)
The
measurement was entirely Mike Martin’s idea, and it proved to be quite
fascinating
[96]. Nothing dramatic, just the
challenge of explaining how can we have
more than 200
IR active vibrational lines, when the
simple theory
only allows for four lines. Years later I was still trying to work out
some of
the details with help from ab-initio
molecular dynamics calculations [114].
116 L. Forró and
L. Mihaly
Electronic properties of doped
fullerenes (review)
Reports
on Progress in Physics, 64 649-699 (2001)
An
attempt to apply the basic concepts of condensed matter physics to
fullerenes [116]. It is a pity the review
went to print before the
shamefully manufactured results of Batlogg
and Schön were exposed.
6.
Recent Works: Perovskite Magnets
and High
Field Electron Spin Resonance
117 L. Mihály,
D. Talbayev, L.F. Kiss, J. Zhou, T. Fehér and A. Jánossy
Field-frequency mapping of the electron
spin resonance in the paramagnetic and antiferromagnetic
states of LaMnO3
Phys.
Rev. B, 69 024414, (2004)
118 Diyar Talbayev, László Mihály, Jianshi
Zhou
Antiferromagnetic resonance in
LaMnO3
at low temperature
Phys.
Rev. Letters, accepted for publication (2004)
Over
the last few years I have been building a new instrument, with the
primary goal
of doing electron spin resonance at high magnetic fields.
I secured $200,000 from NSF and
