Doors of Opportunity
As told by Donald M. Eigler

2010 KAVLI PRIZE IN NANOSCIENCE

MORE ABOUT DONALD M. EIGLER

As autobiographies conventionally begin with the circumstances of one’s birth, and as I am in no way inclined to break with that literary tradition, I want to inform the reader (and I can do this with some degree of confidence) that I was born. The exact circumstances of my birth are unknown to me as I have no recollection of the event, but if I was then as I would be for the rest of my life, it is reasonable to conjecture that it was a bumpy ride. I must someday consult my mother on this point.

As for parents, I was dealt a pair of aces: Evelin and Ike Eigler. The abounding genius of my parents was two-fold. First, they almost never pressured their children concerning academic achievement. In retrospect I find this a curious point, because they certainly had no reluctance to pressure us to get our chores done, mind our behavior, and conform to their model of a properly mannered young person. Second, they strived to create experience and opportunity for us. It is this last point, the creation of opportunity, that we will see is the recurring motif of this story.

My first, and arguably most formative mentor, was my father, Ike Eigler, so just a few words about him. Airplanes, rockets, missiles, helicopters – if it went up in the air, he worked on it, either while a mechanic as a young man or later in life as an aerospace engineer. My father loved to work with his hands. Our garage at home was almost never used for storing automobiles, instead, it functioned as my father’s workshop. He was always in there: fixing or building something – making things work. It was in my father’s garage where I first began designing and building things in the hope that they too would work. I could not have been much more than six years old when I took a couple of pieces of scrap wood, and, with a saw, some nails and a hammer, constructed my first model boat – not from a kit, not from drawings, not from what others told me a toy boat should be, but from my own design. I recall being somewhat crestfallen to discover that it tipped over when I floated it in a tub of water. My father encouraged me to think about why the boat tipped over, but at that young age I hadn’t a clue. So began my career as an experimentalist.

My first physics teacher
It is without doubt that as a young boy emulating his father, I not only became curious about how the world around me works, but also learned that if I was a careful observer and experimenter, I could build an understanding of that world. It is in this context, and with the benefits of hindsight, that I can clearly recognize my father’s influence – he was my first physics teacher.

My high school teachers were largely boring, and I was at best a lackluster student, that is, until my senior year. During this last year of high school I had three excellent teachers, each of whom was intent upon challenging us to really use our minds. Mr. Jerry Ester, who taught physics, was one of them. The challenge started on the first day of class when he announced that instead of using a high-school-level textbook, we would jump ahead to “Halliday and Resnick,” the venerable standard from which introductory physics courses were taught in universities. I thrived.

Mr. Ester was a gifted and enthusiastic teacher. You could immediately tell that he taught physics because he wanted to. He had a particular knack for being able to explain things in a concise, orderly, and satisfying manner. What needs to be said here is that it was Mr. Ester who created for me a delightful and challenging first-experience with the formal aspects of physics. He put the bait on the hook and I went after it.

“He put the bait on the hook and I went after it.”

If it was my high-school experience that whetted my appetite for physics, then it was my undergraduate university experience at Revelle College, University of California San Diego, that sent me irretrievably down the rabbit’s hole to becoming a physicist. I was taking the freshman course in Electricity and Magnetism when I first encountered a man who would play a singularly important role in shaping my career.

The course was taught by a somewhat brash young professor who, although having relocated to the relaxed-paced California community of La Jolla, insisted on wearing his New York City street-tough persona on his sleeve. His lectures and demonstrations were animated by that persona, but it also led to a very difficult, at times even pugnacious, relationship with the students. It wasn’t pretty.

Surfing and girlfriend
Near the end of my sophomore year, I was confronted with the problem of what to do during the coming summer, which I desperately wanted to spend in La Jolla so that I could concentrate on the important things in life: surfing and my girlfriend. “Research!” I told myself. “If I can just get involved with some research I’ll be able to spend the summer in La Jolla.” I liked physics, but the only member of the physics department I had any knowledge of was that guy from New York with the attitude – a person who, at that point in my life, I found somewhat intimidating.

Summer student
So with some significant trepidation I knocked on his door one day. He asked me what I wanted. I told him I was finishing my sophomore year, that I really liked physics, and although I didn’t have a specific project in mind, I wanted to do some physics research that summer. He took a few moments to show me around his labs and told me to come back in a few weeks, after which, if I was still interested, we would discuss it some more. I was enthused. So I went back in two weeks and found, much to my delight, that he was willing to take me on as a summer student doing an independent studies project in his lab. So started my relationship with the man who would become my thesis adviser, my mentor and friend, Shelly Schultz. Many years later I asked Shelly why he never had any other undergraduate students do independent studies with him. His answer: “They never came back after two weeks.”

At the end of summer my independent studies project turned into a job as a research assistant and I would continue in that capacity into my senior year. These formative years in the Schultz lab were pivotal. If it were not for the opportunity of being directly involved in research I doubt I would have ever completed my bachelor’s degree. That opportunity was not something of my own creation. It came because generations of Californians had built a great research university – a university in which academic merit, not social or financial status, was the ultimate metric. And compounding the benefits that came with that opportunity came a very special experience – a kind of magic passed down from generation to generation when a senior scientist takes the raw material of youth under their wing and begins to mold the next generation. The opportunity to learn from one-on-one interactions with Shelly was without doubt the single most important contribution to what success I have had as a scientist. There is really no way to assign value to that kind of experience.

Methodology
The most valuable lessons that came from working in the Schultz group were lessons of methodology. How does one approach a problem? What questions should be asked? How do you check that your results make sense? How do you think like a physicist?

But there were other lessons that without doubt laid the foundation upon which my career would be built. By the time I was in my senior year I was reasonably well versed in the methods of low temperature physics, and, thanks in large part to the training I had at the feet of my father, I could design, build, and make work my own experimental apparatus. These skills would prove of immense value throughout my life.

My upper division years were a difficult and anxiety filled time for me. I loved laboratory research, but found it nearly impossible to concentrate on my course work. The trajectory I was on, if continued unabated, would bring an end to any hope of a career as a scientist. I was taking a class in thermodynamics and doing very poorly – that is, I was flunking – when one afternoon while hitchhiking home, a small red Fiat sports car pulled over to give me a ride. I jumped in only to discover that the driver was the professor of my thermodynamics class. Apoplexy! We drove north without an exchange of words. Nearing the beach town of Del Mar he at last broke the silence with the words “You know you are flunking the course.” I cringed and silently nodded. Then he said just a few words – words deeply steeped in insight and kindness – pivotal words: “It’s alright. I’m certain you can do well. It’s just that right now your mind is busy with other things.” So began my friendship with Dieter Wohlleben.

“It’s alright. I’m certain you can do well. It’s just that right now your mind is busy with other things.”

Dieter Wohlleben was a young adjunct professor working in Berndt Matthias’ group. He was then, as he would be all his life, absolutely passionate about physics… especially if it was the physics he was working on. And one of those things he was passionate about was an idea he had that electrons field emitted from a superconductor would exhibit a coherence that far exceeded the coherence of electrons field emitted from a normal conductor. Furthermore if this were the case, it should allow a revolution in electron microscopy: the creation of electron holograms that would make it possible to resolve individual atoms taking advantage of the phase contrast inherent in the holographic process, and the ability to remove the effects of aberration (at least to first order) in the holographic reconstruction process.

Coherent electron project
It was my senior year. Dieter was pursuing his ideas about coherent electrons on a shoe-string budget and needed some manpower to help him out. He had already observed me doing research in the Schultz group and knew that I could get things done in a lab cheaper and often better than many graduate students. After consulting with Shelly, he approached me about helping him out with his project. I thought it would be fun to give it a try and so started working with Dieter on the coherent electron project.

As it turns out, time was short. Dieter had just been offered a full professorship at the University of Cologne and would soon be moving to Germany. I was soon to graduate. We had but a few months left to work together in La Jolla, a time spent desperately trying to pull together an experiment that would demonstrate coherence. It was against the background of this shared effort in the laboratory that we forged not only a lifelong friendship, but a special working relationship that is worthy of mention: Dieter treated me as an equal. Despite his vastly superior knowledge and experience he would thoughtfully listen to my ideas and suggestions. He was never demeaning. He never talked down to me. He treated me with respect no matter what the circumstance. The opportunity to work under conditions in which you know you are respected for your efforts and contributions is something that is precious, especially for a young scientist. It leads to growth. Dieter gave that gift in abundance.

Germany
The inevitable happened. Dieter moved to Germany to take up his position as professor, and despite my erratic undergraduate academic record, I graduated. I was not ready or prepared for graduate school, but I wanted to continue with research. What to do? Opportunity, once again, came my way. Dieter invited me to take up a position as Research Associate in his institute at the University of Cologne where I would continue the coherent electron project. And so I headed to Germany.

My experience in Germany was transformative. I was given more responsibility and freedom than most of the postdocs, never mind graduate students. I had my own project, my own laboratory and my own full time technician. It was in this environment that I began to see myself in a new light, at least in a professional context. After a year and half in Germany I knew exactly what I had to do: I had to get into graduate school and earn a doctoral degree in physics.

So I applied for entrance as a graduate student in the Physics Department at the University of California San Diego, not long after which I received a form letter informing me that my application was denied. But along with the form letter came a personal letter from the department chairman explaining that in fairness to other applicants they could not admit me based upon my poor academic record, and not-so-stellar Graduate Record Exam scores, however my letters of recommendation indicated that perhaps my academic record was not an accurate measure of my capabilities. He suggested that if I wanted to pursue a degree I could take the same courses that the first-year graduate students were taking, and after a year, if I did well in those courses, then I might be reconsidered for admittance to the doctoral program. “Fair enough,” I said to myself, packed my bags, and said goodbye to my many friends in Cologne.

Determination
The first-year graduate students in the Physics Department started off with three concurrent courses: Mechanics, Electricity-and-Magnetism and Mathematical Methods. I studied as I had never before. The big change – the change due to my experience in Germany – was that now my jaw was set. I had a goal – to become a physicist – and if I failed to achieve that goal… well it wouldn’t be because I failed to bring to bear every ounce of hard work I could muster. And muster I did. I had a very long way to go to catch up with the other graduate students, but I had a secret weapon: determination… an abundance of determination.

After the first quarter, and much to everyone’s surprise (not the least my own), I had aced the three courses, earning the top grade in one of them. I figured it unlikely that I would ever do so well again and so I contacted the department chairman and asked whether I could be re-considered for admission as a graduate student in their doctoral program. Two weeks later I received a letter from him congratulating me on my admittance as a graduate student and welcoming me as a member of the department. I have that letter to this day. It serves to remind me of what can be accomplished when your goal is set and you exert every effort to achieve it. But it also validated Dieter’s perceptive words to a young hitchhiker who was flunking his class in thermodynamics.

I did my thesis research in Shelly Schultz’s lab. The topic of my doctoral thesis was conduction electron spin scattering at atoms adsorbed on a metal surface. While my work with Dieter on the coherent electron project had already exposed me to some of the difficulties of doing experiments on clean surfaces at low temperatures, my thesis research required that I master them. And master them I did. This put me in a somewhat unique position – I was one of the few people on the planet who was steeped in the lore of both the surface physics community and the low temperature physics community. In addition, my work with Dieter had provided me with a firm knowledge of tunneling in general, and the literature and tricks of field emission in particular. The stage was set.

Scanning Tunneling Microscope
I was in my last year of graduate school when I saw an image in a Physics Today article showing monatomic steps on a gold surface. I was long familiar with Russell Young’s work on the “Topographiner” and said to myself: “At last, someone has taken it farther.” I was excited. The image came from a new kind of instrument called a “Scanning Tunneling Microscope” created by Gerd Binnig and Heini Rohrer at IBM’s Zurich Switzerland research laboratory. It was not long until they demonstrated atomic resolution with an image of the adatoms of the Si(111) 7x7 surface. I think it fair to say that that picture of the silicon surface sent a shock wave of excitement through the surface science community and beyond. No more guessing – here were the atoms.

The invention of the Scanning Tunneling Microscope (STM) and the excitement surrounding it had a profound influence on me. It caused me to ask the question: “What could one learn if he had an STM with clean surfaces and low temperatures?” I, after all, had already learned how to simultaneously achieve these conditions, and I was well steeped in the tunneling literature. So I made a list of interesting experiments. The list kept getting longer. I was like a moth drawn to the flame – I wanted to build a low temperature ultra-high vacuum STM.

Bell Labs
Opportunity came my way and I got to do just that. I was offered a postdoctoral position in Gene Golovchenko’s group at Bell Labs where I would build my first STM. It was an intense time, but I did manage to build that first low temperature ultra-high vacuum STM, demonstrate atomic resolution, and make initial attempts to measure the vibrational frequency of an adsorbed molecule. But despite my efforts, I fell short – my two years were up and I had no publications. Many people had warned me about the professional risks of building ambitious new apparatus as a postdoc, but I had decided to take the risk anyway. I had failed at achieving my goal.

How does one get a job with no publications to show for their time as a postdoc? It turns out that it is possible, for it happened to me. Through sheer luck, my search for a job brought me into contact with someone who looked beyond the issue of no publications and decided to take a risk on me. That person was Dan Auerbach, manager of Physical Sciences at IBM’s Almaden Research Center in California. Once again, opportunity came my way.

IBM
I joined IBM as a Research Staff Member in 1986, and set off to build my second low temperature ultra-high vacuum scanning tunneling microscope, but this time with my own lab, generous financial and technical support, and (perhaps even more important) surrounded by colleagues who wanted me to succeed.

It was around 10:00 PM on New Year ’s Eve, 1987, fourteen months after joining IBM, when the first atomic resolution images came. And they were beauties. The new machine was showing a stability and resolution that far exceeded anything I achieved back at Bell Labs, and that exceeded anything anyone was doing at the time. Seeing these images, and despite the fact that I had not yet published anything, Dan Auerbach decided to double down. He walked into my lab one day, looked around, and said “You should get a postdoc.” Soon thereafter Paul Weiss, would join the lab as my first postdoc.

Paul and I spent the ensuing year struggling to get rid of bugs in the machine while simultaneously trying to conduct experiments that would lead to a publication. Our goal was to measure the vibrational frequency of a single molecule or atom on a surface. Along the way we began experimenting with xenon atoms on a platinum (111) surface. We had seen how some rafts of xenon atoms would change their shape (and sometimes their number) from one image to another. It was obvious from the beginning that this was due to an interaction with the tip of the STM. This was nothing new. Even from the earliest days of tunneling on dirty surfaces people would see images that looked like blades of grass, but would find that if they scanned over the same region many times the blades of grass might disappear or be rearranged. The fact that the STM’s tip can change the locations of atoms is known to anyone and everyone who has ever crashed a tip into a surface… a lot of people.

Atomic precision
Paul’s tenure as a postdoc came to an end and Erhard Schweitzer took over as my postdoc. It was at this time that we came to suspect that instead of uncontrollably bashing the xenon atoms around with the tip, we might be able to successfully pull an individual atom from some initial location on the surface to a location on the surface of our own choice, the key idea being that we could use the bonding force between the tip and the atom to pull the atom along the surface without actually transferring the atom from the surface to the tip. Once we knew what we wanted to do, it didn’t take long to write the necessary software to achieve control of the tip’s position, and soon we had demonstrated to our satisfaction that we could manipulate individual xenon atoms on the nickel (110) surface with atomic precision. The rest is history.

Why was atom manipulation possible? Certainly there were many things that contributed to our success, but there are two things most worthy of note: control and stability; control of the attractive force on an atom by the precise (picometer or better) control of the position of the tip, and the stability that comes by freezing out the thermal diffusion of atoms while at the same time creating a level of vacuum that allows surfaces to be kept clean for months at a time. Atom manipulation was made possible by wedding the techniques of surface science and low temperature physics.

Are there any valuable lessons in this story? As we have seen, I just happened to have the skills and training for building a low temperature ultra-high vacuum STM. That was certainly a fortuitous circumstance, but serendipity is difficult to engineer – no lesson here. That there is tremendous power in setting a goal and doggedly pursuing that goal is both well-known and widely espoused as a recipe for a successful career. The power of determination is certainly a valuable lesson, but I think there is a much deeper and vastly more consequential lesson – a lesson which I hope will allow you to excuse the somewhat burdensome length of this story.

The lesson is both simple and ancient: none of us really succeeds on their own. In my case, we have seen that my success was time-and-again attributable to those who, motivated by kindness and endowed with a determination to invest in a younger generation, used their talents and auspices to open doors of opportunity to me. Those opportunities were priceless. Without them, I would have never had a career as a scientist. The only, and I am sure best, way to reciprocate, is to carry their spirit forward by creating opportunities for the next generation of young scientists. In doing so, we not only perpetuate the cycle, but we also avail ourselves of the greatest joy our profession has to offer.