I was born on
April 6, 1949 in a regional hospital in Frankfurt am Main in
Germany. Having the umbilical cord wrapped twice tightly around
my neck, my parents' fear for the mental health of their
first-born son subsided only gradually.
My forefathers had been farmers, inn-keepers, blacksmiths,
carpenters and shop keepers in the region. My mother, an
elementary school teacher, and my father, having finished an
apprenticeship, had been married during the previous year,
shortly after a devastating war. Opening a store for interior
decoration in my father's home town of Sprendlingen, they were
trying to build an existence and start a family at the same time.
Eighteen months later a brother, Heinz, was born without the
umbilical complications.
Sprendlingen, today a part of Dreieich, just south of Frankfurt,
was a town of some 15,000 inhabitants. I was raised in the circle
of an extended family of four uncles and aunts, who, together
with my parents, lived in two houses with barns and sheds and the
store surrounding a large yard. It was an ideal playground for
two boys growing up with their cousins - this group always
extended by a horde of friends. Constructing huge sand castles
with moats and bridges, cardboard tents from the shop's packing
material, building elaborate knight's armour from scrap
floor-covering and intricate race tracks for marbles from curtain
rails remain fond memories of childhood.
I began kindergarten at age three and was soon after joined by my
brother. The kindergarten's seemingly unlimited amount of toy
building blocks must have fascinated me and I soon became
somewhat of the establishment's chief architect. School, at six,
was a happy time, complemented in the afternoons by playing
soccer in our yard, roaming about the fields surrounding my home
town, and building dozens of detailed cardboard model ships and
airplanes from "Ausschneidebögen".
There was never a doubt in my parents' mind that their sons would
receive the best possible education. Although none of my
forefathers graduated from high school, my parents regarded
highly the merits of a good education as a tool for social
advancement. In their value system knowledge always ranked above
wealth - although not rejecting a possible fortuitous marriage of
both. To enter "Gymnasium", at ten, required the passing of a
test. I was accepted and from then on commuted for eight years,
five km each way, to the "Goethe Gymnasium" in the neighboring
town of Neu Isenburg.
Gymnasium was hard. I was not a particularly good student. I
loved mathematics and the sciences, but I barely scraped by in
German and English and French. Receiving an "F" in either of
these subjects always loomed over my head and kept me many a year
at the brink of having to repeat a level. Luckily there was
"Ausgleich", balancing a bad grade in one subject with a good
grade in another. Mathematics and later physics got me through
school without repeat performance. I also excelled in sports,
particularly in track and field, where I won a school
championship in the 50 m dash. But sports could not be used for
"Ausgleich".
One of my teachers stood out, Mr. Nick. He taught math and
physics. A new teacher, basically straight out of college, young,
open, articulate, fun, he represented what teachers could be
like. His love and curiosity for the subjects he was teaching was
contagious. As 15 or 16 year-olds, we read sections of Feynman's Lecture Notes
in Physics in a voluntary afternoon course he offered.
Having mastered wooden building blocks and cardboard models,
passed erector sets and toy trains, I had reached the level of
"Elektro-Mann" and "Radio-Mann". Dozens of telephones and light
boxes to communicate between the sheds at home were designed,
constructed, improved, and mercilessly wrecked, possibly
foreshadowing my later employment by a communications company.
And then, of course, there was chemistry, a subject I did not
appreciate in school, but it held the secrets for making
explosives. I built a rocket that propelled a modified car of a
toy train into the air. After several exhilarating launches, the
rocket exploded in my hand and ripped off half my right thumb. I
learned an important lesson: a rocket and a bomb differ only in
the exhaust. Affecting me somewhat during adolescence, the
missing thumb also relieved me from army duty. Today, it is only
an unimportant, physical curiosity.
I always wanted to become a physicist. Supposedly, at age six, I
had told just that to a technician, who was repairing a TV set in
our home. Obviously, I had little clue as to what a physicist
did. Nevertheless, the goal persisted all through high school,
but suddenly got overthrown during the last year of "Gymnasium"
when an art teacher discovered my talent for design. I passed my
baccalaureate with average grades - quite good in the sciences
but quite poor in the humanities - and started to study
architecture at the Technical High School in Darmstadt, about 20
km south of my home town. Being too late at application time, I
had to register for "Lehrfach für Bauwesen", a related
subject, that consisted of similar freshmen courses as
architecture. I turned out to be very good in making any
technical drawing of a bird cage from any requested angle, but
very poor in freehand drawing and decided that architecture was
not for me. Instead I went on to pursue my true love -
physics.
As with architecture in Darmstadt, I was too late for
registration in physics at the Goethe University in Frankfurt and
took up mathematics instead, transferring to physics the
following year. The year was 1968. Student revolts swept the
campuses from Berkeley to Berlin. Frankfurt was a major site for
riots in the streets and in the lecture halls. For a young
student, hardly familiar with university life, largely ignorant
of the aim of the different protests, these were uncertain times.
Legitimate educational reform requests became confused with
larger political issues leading to absurd happenings around
campus. Damage was done to the institution of the university and
its teaching staff but, at the same time, 1968 marked the
beginning of a gradual and rational reform.
Studying physics and mathematics was wonderful. It was a far cry
from Gymnasium. I loved the rigor of mathematics. In physics we
had fascinating beginners lectures by two descendants of the
famous "Pohl School" of Göttingen, Prof. Martienssen and
Prof. Queisser. I had joined a group of likeminded students that
studied together and hung out in "Café Bauer" for
relaxation. Life was good, until I took the "Vordiplom", the
major exam in all courses at the end of the fourth
semester.
All physics and math exams - some six to eight written or verbal
tests - went very well. They went so well, that I thought I
needn't study at all for the dreaded verbal chemistry test. With
straight "A"s in physics and mathematics, what was the chemistry
professor to do but let me pass? I was mistaken and flunked
badly, requiring all tests to be taken again, six months,
later. Thankfully, physics and math professors - some having had
experiences of their own with chemistry tests - conspired and
promised to maintain my grades in those subjects. It gave me six
months, to study nothing but chemistry. I never felt more
confident walking into an exam and succeeded getting an "A" in
chemistry. I had been wary of the field of chemistry
throughout high school and during much of my studies. Counting
valences and bonds, memorizing dozens of exceptions to the rules
and hundreds of arcane compounds never made much sense to me. I
came to revise my attitude towards chemistry once I had grasped
quantum mechanics and the origin of the chemical bond.
The thesis work for my Diploma - in Germany a required step
towards the Ph.D. - was performed in Professor Werner
Martienssen's Physical Institute under the supervision of a young
assistant professor Eckhardt Hoenig. Professor Hoenig had just
returned from the United States, where he had worked on
highly-sensitive superconducting detectors, so-called SQUIDS. The
aim was to use these new devices to study the magnetic properties
of hemoglobin to derive the geometry of its bond with oxygen. It
was a time of immense joy paired with intense learning of
intricate low-temperature techniques. Hoenig was a wizard in
inventing and building sophisticated instrumentation to attack
physics questions. Gerd Binnig, who later
shared the Nobel Prize for the invention of the Scanning
Tunneling Microscope, was another student of a total of four
working with Hoenig at this time in the same lab. It is probably
coincidental, nevertheless, I believe our education in
experimental physics down in this basement of the "Neubau" was
second to none and strongly affected our experimental approaches
throughout our careers. Hemoglobin did not bow to our
instruments, at least over the course of a year, and I quickly
performed some measurements on iron impurities in magnesium. I
wrote an unimpressive diploma thesis on the magnetic anisotrophy
of their susceptibility and received the necessary license to
start with a Ph. D. thesis.
At this time, my horizon unexpectedly widened. It had never
occurred to me, nor to many of my town's youngsters, to go to
university anywhere else but Frankfurt or Darmstadt. We went to
the closest one and lived at home, where our families had been
based for generations. However, in the fall of 1974, a former
student from Frankfurt, Wolfgang Kottler, visited. He had since
moved to Grenoble, France, where the Max-Planck-Institute for
Solid State Research in Stuttgart was operating a high-magnetic
field facility together with the French National Center for
Scientific Research, CNRS. He was just finishing his Ph.D. thesis
under Professor Hans-Joachim Queisser and was beating the bushes
for his own replacement in Grenoble. Initially hesitant to make
such a big step, moreover to a foreign country, the mastery of
whose language I largely failed in school, I visited Grenoble and
asked myself: Why not?
Going to Grenoble was the single most important step in my life.
Leaving the familiar surroundings of home, diving into another
culture, another language, meeting new people, making new friends
was initially frightening, but eventually immensely educational
and gratifying. Meeting my wife, Dominique Parchet, in Grenoble
certainly added to the city's attractions. Grenoble, at the edge
of the Alps, not far from Switzerland was the French Science
City. The magnet lab had been established only a few years back.
Professor Klaus Dransfeld was the local director. There existed a
frontier atmosphere with an exhilarating "can do" sentiment. It
was an international place. Many famous scientists passed through
and, due to the informality surrounding the lab, even the
students were able to meet them on a very personal basis. This
was quite different from other, more hierarchically structured
research institutes. In a certain sense, students were kings at
the magnet lab. They knew all the ins and outs of the magnets and
the visiting collaborators were willing to share their scientific
knowledge with them in return. It also was there, I first met
Daniel Tsui from
Bell Labs.
My thesis project was to work on the properties of electron hole
droplets in high magnetic fields, a subject that had been
proposed by Dieter Bimberg of the magnet lab. I was joined by
Rolf Martin, who had just received his Ph.D. from the University
of Stuttgart. Together we spent hundreds of immensely enjoyable
and very productive research hours - daytime or nighttime -
around the colossal magnets. Sharing a French "villa" with Ronald
Ranvaud, where many distinguished visitors from abroad were often
guests, life revolved totally around science. I finished my
thesis in just over two years and received my Ph.D. from the
University of Stuttgart, where my thesis advisor, Prof. Queisser,
now a director at the Max-Planck-Institute in Stuttgart, held the
position of an honorary professor. Instead of the usual
dedication, my thesis had started with a cartoon. I learned only
recently, that this had been a major cause of irritation and that
removal of the cartoon as well as cutting my shoulder-length hair
could barely be warded off.
All through my Ph.D. years, Prof. Queisser had urged me to finish
my thesis swiftly and move on to the United States. He himself
had been in the US, working at Bell Labs and later with Shockley,
one of the inventors of the transistor. Bell Labs, the research
arm of American Telephone and Telegraph (AT&T), was the
"Mecca" of solid state research. Strongly encouraged and
supported by my thesis advisor, I had visited Bell Labs and
worked with John Hensel on electron hole droplets for several
weeks during the spring of 1976. The visit was also intended to
make contact with Raymond Dingle of Bell Labs. At the time, he
was working on semiconductor quantum wells, an exciting new area
of research made possible by the invention of molecular beam
epitaxy (MBE) in the late '60s by Alfred Cho, also of Bell Labs.
I had heard Dingle speaking on the topic at the 1975 March
meeting of the German Physical Society and had decided that
this was the subject I wanted to pursue. As it turned out
Queisser knew Dingle personally and with partial financial
support from the Max-Planck-Institute in Stuttgart I was accepted
into a consultant position in Venky Narayanamurti's Department,
working effectively as a postdoc with Ray Dingle. I moved to Bell
Labs in June 1977.
Modulation-doping, the technique to generate ultra-high mobility
two-dimensional electron systems, instrumental for practically
all of my later research, was conceived about two weeks after my
arrival at Bell Labs in a conversation with Ray Dingle. In his
office, he had outlined their recent efforts to introduce free
carriers into semiconductor superlattices and had sketched the
positions of band edges, impurities and electrons on his
white-board. It occurred to me that by placing impurities
exclusively into the potential barriers, while keeping them out
of the potential wells, the scattering of electrons by impurities
should be reduced, thus increasing mobilities. It was a casual,
almost trivial observation, which, however, turned out to have
big impact.
Modifications to the MBE crystal growth instrumentation of Arthur
Gossard and his assistant William Wiegmann to allow for such a
selective doping were made over the course of a few months, and
they demonstrated the anticipated gains in mobilities. Initially,
mobilities improved by a mere factor two or three over
conventionally doped superlattices, but they have since grown by
another factor of ~1000. Loren Pfeiffer and Ken West, both from
Bell Labs, have led this effort and have consistently provided
the most exquisite samples for research. Much of our experimental
success rests on our direct access to their "candy store".
Modulation-doping gained me a permanent position at Bell Labs in
the fall 1978, and I was soon joined by my long-time assistant,
Kirk Baldwin. With such high-quality material available, many
physics experiments - previously conducted on two-dimensional
electron systems in silicon - became feasible in gallium
arsenide. It also opened the door to many optical experiments on
two-dimensional electron systems, largely performed by Aron
Pinczuk and his colleagues at Bell Labs in Holmdel.
At the time, Dan Tsui of Bell Labs was already recognized as one
of the world's leading experts on two-dimensional electron
systems in silicon. He quickly recognized the potential of the
new material for research and invited him on his frequent trips
to the MIT Francis Bitter High Magnetic Field Lab in Cambridge,
Massachusetts. It was the beginning of a scientific collaboration
and personal friendship, which has lasted now for almost 20
years.
The quantum Hall effect, having just been discovered in 1980 by
Klaus von Klitzing, was a major topic of our research. Another
topic was the electron crystal, which was theoretically predicted
to form in very low electron density samples in very high
magnetic field. An exceptionally high quality, low electron
density specimen had just been fabricated by Art Gossard and
Willy Wiegmann. Dan Tsui had succeeded in contacting it
electrically, and in October 1981 we took it to the Magnet Lab to
look for signs of an electron crystal. What we discovered
instead, during the evening of October 6, was the fractional
quantum Hall effect.
Since this discovery, many outstanding graduate students (Gregory
Boebinger, Robert Willett, Andrew Yeh, Wei Pan), postdocs (Albert
Chang, Hong-Wen Jiang, Rui Du, Woowon Kang) and colleagues (James
Eisenstein, Peter Berglund) joined us and made discoveries of
their own in this fascinating research area. Other postdocs
working with me (Edwin Batke, Rick Hall, Joe Spector, Ray
Ashoori, and Amir Yacoby) have performed research in neighboring
areas, but affected our thinking in lower-dimensional physics in
general.
In 1983, I was promoted to head the department for Electronic and
Optical Properties of Solids. Administration was a minor chore
during those days, and I could continue to pursue my own
research, practically full time. They were very exciting and
intense research days during which the fractional quantum Hall
effect and its implications were established in many laboratories
around the world. Theoretical progress was rapid and
exhilarating.
In 1991, I was promoted to director of the Physical Research
Laboratory, heading some 100 researchers in eight departments in
William Brinkman's Physics Research Division at Bell Labs. The
time available for my own research dwindled, but I was
compensated by becoming exposed to a wide range of exciting
research topics. The initial satisfaction faded when the physical
sciences at Bell Labs came under strong pressure from management
to contract. These were difficult years, not just for me, but
much more so for many of my friends and colleagues at Bell Labs.
I was reminded of Gymnasium and the power of teachers. With the
split-up of AT&T in 1996, the creation of Lucent
Technologies, which subsumed Bell Labs, and a change of
leadership, the physical sciences at Bell Labs are blossoming
again today.
I always had thought of becoming a teacher one day. Being totally
immersed in exciting research at Bell Labs, the idea had faded.
It was resurfacing. I stepped down from my position in the Summer
of 1997 and joined Columbia University in January of 1998 as a
Professor of Physics and Applied Physics, while remaining Adjunct
Physics Director at Bell Labs, part-time.
From Les Prix Nobel. The Nobel Prizes 1998, Editor Tore Frängsmyr, [Nobel Foundation], Stockholm, 1999
This autobiography/biography was written at the time of the award and later published in the book series Les Prix Nobel/ Nobel Lectures/The Nobel Prizes. The information is sometimes updated with an addendum submitted by the Laureate.
Copyright © The Nobel Foundation 1998
Horst L. Störmer
