Professor Bruce M. Clemens
Professor Clemens discusses his career at Stanford and what he plans to accomplish as he begins his new chapter in retirement.
What inspired you to pursue a career in Materials Science and Engineering?
I have had what might be termed a non-linear path to becoming a Professor of Materials Science and Engineering. After a halfhearted start at an ill-defined, non-technical college major, I switched to technical classes to prepare to become an oceanographer, having always loved the sea. I quickly found myself overwhelmed – the half-hearted approach that worked so well in high school and worked ok in the non-technical classes didn’t cut it in calculus, physics, and chemistry. I was not doing well, so I dropped out.
I moved to Denver, Colorado, and found a job at a tube bending shop. I bent all sorts of tubes, from huge 5-inch diameter tubes with half-inch thick walls to tiny tubes where I could fit the whole run of hundreds of parts in the palm of my hand. We used a draw bender, where the metal in the tube is subjected to massive plastic deformation. Sometimes the tubes broke. I learned that annealing could help with some metals, but I did not understand why.
After a couple of years, I decided to give college another try and enrolled in night classes at the Denver campus of the University of Colorado. I found I enjoyed working through complex homework problems, and I turned out to be pretty good at it. The engineers at the tube bending shop told me that the Colorado School of Mines would be more challenging, so I transferred there, eventually graduating in Engineering Physics at the top of my class. Along the way, I finally left the tube bending shop and supported myself by working in a lab in the Physics Department. I found that doing research was WAY more fun than bending tubes. I majored in physics because I liked the connection between analytical models and physical situations. Plus, it was supposed to be the most demanding major at CSM, and I thought problem-solving skills would be a good background for any field. I still think this last part is true. I minored in metallurgy and took a class from David Matlock, an alumnus of the Stanford Matsci department.
I applied to many graduate schools in Physics or Applied Physics and a couple in Oceanography. I ended up going to Caltech in Applied Physics because it seemed like it would be challenging and, again, seemed like it would be a good background for any field. I still didn’t know what I wanted to do with my life.
At Caltech, I joined the group of Professor William Johnson. I remember when he interviewed me for a position in his group. He had a project that involved phase separation and crystallization in amorphous metallic glass superconductors. He thought it might involve something called “spinodal decomposition.” He said, “of course, you know all about that since you have a metallurgy background from Mines.” I had never heard of spinodal decomposition, but I chose to remain silent on that issue and not disabuse him of his assumption. After our meeting, I headed to the library and got a copy of every paper I could find on spinodal decomposition. It turns out to be a fascinating phenomenon described with a beautiful mathematical treatment. I think this was the first somewhat advanced subject that I taught myself and my first exploration into the solid-state thermodynamics and kinetics that form much of the foundation of materials science.
My graduate work was on amorphous superconductors, but I studied many materials-related phenomena, including phase separation and crystallization. I had the habit of getting to work early, probably left over from my time in the machine shop, while the rest of the group, including my advisor, preferred to get in late and work late. Often when we had visitors, I was the only one there. As a result, I got to spend a lot of time meeting famous scientists, including Walter Harrison and Mac Beasley from Stanford and David Turnbull and Frans Spaepen from Harvard. Meeting David Turnbull was incredibly impactful, as I had studied his foundational papers on nucleation when I was working on water droplets formed over coal dust particles while working in the lab at CSM. He was a giant in the field. His interest in me and my work gave me a vision that there might be a place for this former tube bender and college dropout in the scientific community.
When Peter Haasen, a world-renowned physical metallurgist from Germany, visited, I was the only one there, as usual. After we spent time discussing my research and seeing the lab, he asked if I could take him to the bookstore. Professor Haasen was a formal dresser in a suit, white shirt, and tie. I was wearing my regular starving grad student rags and, at the time, had a long beard and ponytail. As we walked to the Caltech bookstore, Professor Haasen remarked that everybody sure dressed casually here. Just then, Richard Feynman jogged by in the company of a bunch of undergrads, wearing running shorts and shoes. I quipped, “yes, everybody here dresses casually; there goes Richard Feynman, for example.” Later I learned that Peter Haasen was a frequent visitor and great friend of the Stanford Department of Materials Science.
Toward the end of my Caltech studies, a friend, Bai-Xin Liu, mentioned that he was working in layered thin films that were mixed by bombarding with ion beams. Based on their composition, I thought they might be superconducting. Sure enough, they were. We studied their superconducting properties, working night and day over a relatively short period to get a paper out.
After Caltech, I worked at the General Motors Research Labs in Warren, Michigan. My oldest son was 13 days old when my wife and I moved to Michigan, where we knew no one. At GM, I started an effort in thin-film materials science and studied thin film reactions, with an activity in characterizing multilayered films with x-ray diffraction. I think it was the bootlegged study on ion beam mixed layered films at Caltech that got me hired at General Motors.
At GM, we had a great library system where journals could circulate to your desk, so I was able to read all the relevant papers. I found this very helpful because before going to GM, I knew almost nothing about the science and technology of growing and characterizing thin films. GM was a great place to work with many fantastic colleagues and generous support from what was at the time the company with the largest research and development effort in the world. In particular, I benefited greatly from interacting with Jack Gay, a theoretical physicist, and Gary Eesley, a laser scientist.
After five years at GM, I volunteered to participate in a scientist exchange program with Hughes Research Laboratory. GM had just bought Hughes, and they wanted better connections between the two research laboratories. So in 1988, I headed to HRL, located in the Malibu, California hills overlooking the ocean. It was a fantastic experience, and I had a great time interacting with my new colleagues, including Greg Olson, John Roth, and Richard Miles, with whom I formed life-long friendships. During this time, I was appointed to be a visiting professor at Caltech and took the opportunity to take a class on using transmission electron microscopy.
What brought you to Stanford?
Around the time I headed to Malibu, I invited Professor Sinclair from Stanford to come and give a seminar at GM. After his seminar and dinner, while standing in a sleet-soaked parking lot in Warren, MI, he mentioned that the Department of Materials Science was searching for someone in the area of kinetics. At the time, I wondered why he was telling me this, but it finally dawned on me that he was suggesting that I might apply for the position. I honestly didn’t know what Materials Science meant, and, further, I was not sure what kinetics was. But I applied, keeping a manilla folder on my progress that I labeled “Long Shot.” I already knew some of the Stanford faculty from graduate school, and during the interview, I got to know Bill Nix, John Bravman, David Barnett, Stig Hagstrom, Artie Bienenstock, and others. I was in awe and humbled that this group might want me as a colleague. But the most fun part of the interview was meeting with the students. They were brilliant, funny, and kind. I finally knew what I wanted to do with my life.
What department changes have you seen during your time at Stanford?
It is hard to compare the department that I joined with the one that exists today. Most of the faculty was senior, and our reputation was mainly in structural materials and mechanical properties. We had a very strong external reputation, but within Stanford, I believe it was felt, perhaps unfairly, that we were a bit old-fashioned and were not taking advantage of being in silicon valley. Over the years, this has changed considerably. Our faculty are leading exciting new research areas in energy, health, and information science, and our internal and external reputations are strong.
What is your primary area of research, and how has it evolved during your career?
At Stanford, I started researching the growth and properties of thin films. We studied structure, mechanical properties, magnetic properties, and thin film devices. We developed in-situ techniques for studying properties during growth, which opened new windows for understanding structure-property-processing relationships. As time passed, we transitioned from understanding behavior to trying to control behavior. For example, we grew intricate magnetic spin valve devices and worked to control the work function in electrodes for transistor gates. In the early 2000’s we began work on hydrogen storage and developed nanoparticle portals for hydride nucleation and hydrogen transport. We also started working on solar cell materials and nanoparticles for catalysis. So we went from exploring nature to trying to control nature. I think this reflects a change in the outlook of our students, from being curious about the world around them to a desire to effect a positive change in the world.
What are your greatest successes or accomplishments during your career?
I am most proud of the work of my students. I am grateful for the faith my students showed in me by joining my group, and I feel extremely lucky to have been able to work with this group of talented and amazing people. I am also impressed with what they have gone on to accomplish, and I look forward to staying in touch in future years. Thanks largely to my students and colleagues, my career at Stanford has been fun and rewarding, but I also do not regret a single moment I spent with my family or enjoying the outdoors.
What were the most significant challenges you faced in your career?
One of the most challenging positions I held at Stanford was as Department Chair. Due to retirements, and a lack of hiring, our department shrunk to a subcritical size and was in danger of being dissolved into other departments. This constant challenge for existence was stressful and led to me having an unproductive, defensive attitude at times. Luckily, I had the support and assistance of the other faculty, particularly Professor Dauskardt, the Associate Chair. Together we crafted growth plans that convinced the Dean to invest in our department. We managed to hire some fantastic young faculty, which was the start of the rejuvenation of our department that was carried out brilliantly by the subsequent chairs, Professor Sinclair, Professor McIntyre, and Professor Salleo.
Later in my career, I had the opportunity to have other leadership positions, including President of the Materials Research Society. I often wished that I had had those experiences before being Department Chair.
What advice would you give to students as they begin their careers?
Be curious, and don’t be too particular about what you work on.
Do you have any parting wisdom for new professors and students who want to be professors?
I have been a mentor for several of our young(er) faculty, but I have to say that I learned more from them than they did from me. Their creativity, drive, and insight have been inspirational. So, I hesitate to give advice! I guess I would say to have faith in your ideas, value your results, and don’t obsess over failures.