Men of Physics: Karl Lark-Horovitz. Pioneer in Solid State Physics

292 Pages·1969·10.156 MB·English

by  V. A. Johnson and D. ter Haar (Auth.)

FRONTISPIECE: Photograph of oil painting of Karl Lark-Horovitz
executed in 1954 by Mr. Raymond Breinin, then of Chicago, now in
New York—commissioned by colleagues, friends, and former
students of K. L-H.
MEN OF PHYSICS
KARL LARK-HOROVITZ
Pioneer in Solid State Physics
BY
V. A. JOHNSON
Professor of Physics, Purdue University
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Preface
UP TO December 1941, Karl Lark-Horovitz was known to his
colleagues in the United States and abroad for important work in
structure determination by X-ray and electron diffraction methods,
for his vigorous pursuit of knowledge in the then-young field of
experimental nuclear physics, and for his herculean efforts in
creating a significant graduate programme and research effort at
Purdue University during the preceding decade.
In January 1942 he was invited by H. M. James, who acted as
a representative of the Radiation Laboratory (operated for the
U.S. Government by the Massachusetts Institute of Technology),
to participate in the war research effort by carrying out for the
Radiation Laboratory certain investigations related to the improve­
ment of radar techniques and devices. Lark-Horovitz agreed to
do this by working on "crystals". Furthermore, he suggested that
he and his associates concentrate, at least initially, on the element
germanium by studying its physical properties and its use in
devices, especially rectifiers. During the next three years Lark-
Horovitz and the members of his Purdue group achieved the
production of high-purity germanium, learned how to control
the electrical behaviour of germanium specimens by the syste­
matic addition of properly chosen impurities, interpreted the
observed electrical and thermoelectric behaviour of germanium,
and applied their knowledge to the improvement of devices used
in radar.
The war-stimulated research carried out at Purdue University,
along with related studies made at a number of other U.S.
universities, several industrial laboratories, and certain labora­
tories in Great Britain, strongly stimulated the growth of the field
vii
VÜi PREFACE
that came to be called solid state physics. After 1945 this field
expanded explosively, both in terms of numbers of physicists
involved and in variety of problems investigated.
Upon the cessation of World War II hostilities, Lark-Horovitz
chose to continue and extend his studies of germanium and other
semiconducting materials. He initiated research on the effects of
radiation upon the behaviour of semiconductors. His world-wide
reputation as a solid state physicist was greatly enhanced by these
radiation studies. Quite appropriately, the bulk of his publica­
tions reproduced in this volume deals with this topic.
It was my privilege to be a graduate student at Purdue during
the 1930's and thus to participate in a small way in the building
of the department. I was selected by Lark-Horovitz in 1942 to
join the group studying the characteristics of germanium and other
semiconductors. From then on until 1958 I was fortunate in
having the opportunity to collaborate with him on a number of
investigations in solid state physics. Much of the material in
Part 1 is derived from my personal knowledge of the events
described.
I have also had the privilege of drawing on the material gathered
by four of my colleagues for an informal memorial meeting held
in April 1958. I thank Professors H. Y. Fan, D. J. Tendam,
I. Walerstein, and H. J. Yearian for their courtesy in allowing me
to quote from their remarks on this occasion. I also thank
Professor H. M. James for his permission to quote from a
memorial statement that he prepared. Professor R. W. Lefler has
been very helpful in providing material pertaining to Lark-
Horovitz's service on the American Association for the Advance­
ment of Science Cooperative Committee. I also thank these
gentlemen for their suggestions during the course of preparation
of the manuscript, and I also acknowledge the encouragement
given by Professor R. W. King, the present Head of the Purdue
Physics Department, and appreciate receiving his permission to
draw material from the files of the Department.
Finally, Mrs. Betty Lark-Horovitz, who has read the entire
manuscript, offered a number of cogent suggestions for its
PREFACE IX
improvement. She has also supplied some details of the early life
of her late husband.
I also express my appreciation to Mrs. S. Louisa Spencer for
her assistance in the preparation of the manuscript.
West Lafayette, Indiana VIVIAN A. JOHNSON
I
Introduction
KARL LARK-HOROVITZ was a latter-day Renaissance man, a man
of many parts, a man with tremendous impatience and unbounded
enthusiasm in his eager search for knowledge. No field of intellec­
tual or artistic endeavour failed to capture a share of his interest
and attention. The breadth of his viewpoint and range of his
education enabled him to achieve professional success which may
be classified into four fields: (i) research in the wide variety of sub-
fields of physics in which he personally participated, (ii) the crea­
tion of a highly regarded graduate programme in physics at
Purdue University, a feat involving both the acquisition of
facilities in the face of tremendous difficulties and the stimulation
of young physicists to develop their own talents to the utmost,
(iii) service to the educational system of the entire United States
by his active participation in the creation, development, and
fruition of the AAASt Cooperative Committee on the Teaching
of Science and Mathematics, and, finally, (iv) his personal efforts
and achievements in the renascence and unfolding of the field
now known as solid state physics.
He was born Karl Horovitz in Vienna, Austria, on July 20,
1892, the son of Moritz and Adele Horovitz. His father, a noted
dermatologist, pursued scholarly interests in fields as divergent
as botany and the works of the Roman poet Horace. With such
a family background, it is not surprising that the young Karl
attended the humanistic high school rather than the engineering
one. He entered the University of Vienna in 1911 and pursued
studies in chemistry, physiology, physics, and pre-Socratic
t American Association for the Advancement of Science.
3
4 MEN OF PHYSICS! LARK-HOROVITZ
philosophy. His studies were interrupted for four years by service
as an officer in the Signal Corps of the Austrian Army and
recuperation from wounds received in service. He married on
July 26, 1916. His wife, Betty, is still living.
In 1919 Horovitz returned to the University of Vienna and
received his Ph.D. degree in physics later that year. The develop­
ment of his productive professional career will be taken up in the
ensuing chapters.
One of his fields of scientific interest was the physics and
chemistry of glass. He also had an avocational interest in glass and
other ceramics, acquired a personal collection of fine quality, and
responded most willingly to the many invitations to discourse on
the history and technique of glass-making at a "popular" level.
He had a considerable knowledge of music and played the violin
and viola. In his early years at Purdue University he organized a
string quartet which played regularly. He was a member of one
chamber music group or another from that time until he was forced
out of participation by the demands of his war-time activities in
research and education. Those fortunate enough to meet him
readily became aware of his ability as a conversationalist and his
solid acquaintance with literature, art, history, and politics.
Most impressive of all his attributes was his complete devotion
to science. Professor H. Y. Fan, colleague and friend of Karl
Lark-Horovitz, spokef about this characteristic as follows:
"We have all seen his bad humour at times. Perhaps he was
loaded down with uninteresting work, such as problems of
administration. When you came into his office he would be
frowning, but as soon as you began to explain to him the research
problem that puzzled you at the moment, or to describe some
interesting result just obtained, you immediately saw the sign of
interest reflected in his eyes. He never became impatient when a
problem of real scientific interest was discussed. This devotion to
science enabled him to be a strong administrator, because he felt
compelled in the interest of science to attend personally to various
t Quotation from words spoken in April 1958 at an informal memorial
meeting.
INTRODUCTION 5
phases of departmental affairs, and to be at the same time an
active research worker in a very true sense of the word. You may
have seen him talking on the telephone to people in the administra­
tion building, or long-distance to some one in Washington,
talking about all sorts of things, but the moment he put down the
phone he would pick up the trend and continue the discussion of
the research problem as if there had been no interruption. This
could come about only because he was really interested in the
physics he was discussing with you."
The family name was changed in 1926 from Horovitz to Lark-
Horovitz. In doing this, Karl Lark-Horovitz linked his wife's
name as an artist-print-maker to his own, a change that was the
result of a definite wish on his part. Later, he wanted his children
to carry on the name of Lark only. Karl and Betty Lark-Horovitz
had two children, a daughter, Caroline Betty, and a son, Karl
Gordon, born in the United States in 1929 and 1930, respectively.
Karl Gordon, like his father, is a scientist. He and his wife,
Cynthia Thompson Lark, are engaged in research in the field of
molecular biology, in which they have published widely.
Karl Lark-Horovitz died, of a heart attack, on April 14, 1958,
while at work in his office in the Physics Building of Purdue
University.
π
The Early Years (1914-1928)
KARL HOROVITZ'S first publication! appeared in 1914, during his
student years at Vienna. It dealt with the historical development
of the physical concepts of relativity, a topic consistent with his
lifelong interest in the history of science. Two more papers were
prepared before his studies were interrupted by World War I.
These are indicative of his bent to explore in newly opened fields.
In this case Fritz Paneth and he used radioactive materials (ThB,
ThC, Po, and Ra) contained in solutions of various acids and
bases to study adsorption by a number of different salts.
After receiving his Ph.D. in 1919 Dr. Horovitz stayed on at the
University of Vienna until 1925 in a position combining research
and teaching. His first project combined his interests in physics
and physiology and led to a series of papers on the physics of
image formation by the human eye. In particular, he described
the influence of physical phenomena on visual acuity and the
apparent image size (Selection 1 of Part 2).
Horovitz also carried out a study resembling his earlier work
with Paneth in that radioactive materials were used in the investi­
gation of a physical process. He used ThB and ThC to study the
structure and surface characteristics of platinum crystals. His
final work at Vienna was concerned with electrochemistry,
primarily the electrode functions and other electromotive proper­
ties of glasses.
"It was in 1925 that Karl Horovitz was awarded an International
Research Fellowship by the Rockefeller Board. $ This was the
t A complete list of publications is given at the end of Part I.
t Quotation from words spoken by Prof. I. Walerstein of Purdue University
in April 1958. Walerstein was at Toronto during Lark-Horovitz's stay there.
6