Billy "Trey" Cole, 2020 NIST Research Intern

Biography

SPS Chapter: West Virginia University

I am a graduating senior at West Virginia University receiving my B.S. in Physics with an emphasis in computational Physics. I have been involved in research at the Physics department since my sophomore year, through which I study topological phases of matter and its applications to superconducting qubits. In the beginning, this consisted mostly of trying to learn the basics, but today I am writing code to simulate nanoscale systems and conducting independent research projects, something I really enjoy and hope to make into a career. Now this summer, despite not being able to participate in person, I will be expanding my research experience as a NIST intern. This is a great milestone for me and I really feel that my hard work as an undergraduate is coming to fruition.

Outside of research, I enjoy music, reading, and adventuring in nature. In West Virginia, there is an ample amount of natural beauty to discover, and a walk through the woods is a great way to clear my mind. I hope that someday I will be able to travel and see more natural wonders of the world.

Internship

Host: National Institute of Standards and Technology (NIST)

Project

Abstract

Kelvin probe force microscopy is a technique in material imaging that can provide sub-nanometer scale spatial resoltuion. The instrumation that makes this possible relies on the vibration of a cantilever, microns in size, that reflects the changes in surface potential of the imaged surface. There have been recent attempts at using KPFM to image subsurface properties, which is relevant in integrated circuit devlopement in particular, along with many other applications. My aim was to construct an appropriately sized cantilever and measure its eigenmodes of vibration under the influence of various driving forces using the COMSOL multiphysics software.

Final Presentation

Internship Blog

Week 1: Highs and Lows

The first week has come to a close, it has been great to become acquainted with the other interns and to meet with my mentor for the summer. I didn’t know what to expect when we got the email that we would no longer be able to conduct our internships in person. It was upsetting news because I knew that we wouldn’t be able to get much of the experience that comes with being able to physically take part in the planned activities for the summer. This was around the same time that classes at universities began to switch to online protocols. Since then, after experiencing some of the trials and errors of virtual meetings, I have gained a more positive outlook. Besides the struggles of latency issues and the lack of physical presence, working virtually is not the hindrance that I was expecting. We had a creative and fun orientation thanks to the team of organizers: Mikayla, Kayla, Brad, the HR team and the others that we have not been in direct correspondence with, thank you all for your dedication to giving us a fun and benefiting summer. Upon introduction, the realization that everyone is in this together really set in.

Following the orientation, I was able to meet with my mentor at NIST and we began to discuss the project he had in mind for me this summer. The nature of the research conducted at NIST is typically hands-on experimental work, something I was hoping to learn more about. However, our plan to run computational simulations is something that I have prior experience with and am happy to work on. I am excited to discover more about the project and add some new things to my repertoire of experiences.

Despite all of the wonderful experiences I have had this week, they will likely be overshadowed in my memories by the horrible atrocity that took place in Minneapolis the week prior to our internship beginning. I was frustrated and angered that this has happened, again. Too many times have I read the news to see that an African American has been stricken down at the hands of a police officer. Americans, regardless of their gender, race, or religious beliefs should have the ability to live their lives peacefully and without descrimination of any kind. Unfortunately, the inequalities that have plagued our country since its inception are still occurring. I stand with the African American community in this time of turmoil and hope that they will find the equality they deserve.

Week 2: Vibrating Cantilever

We are now through our second week, and it was a somewhat slower paced week compared with the first week. After the rush of introductions, first meetings, and preliminary discussions for projects, this week has been mostly waiting for the next step in the plan of action. I was directed to some literature and now have a firmer grasp on the nature of my project. The project is related to atomic force microscopy (AFM) which measures the potential surface of nano-scaled devices using the vibration of a nano-meter scaled vibrating cantilever. Semiconductor devices are ubiquitous in our technological society and up to 50% of the manufacturing steps could be measurement and characterization. AFM measurement is a state-of-the-art technique for this process of metrology for these devices. AFM has also been used for imaging of molecular sized biological materials.

The first adversity of the virtual internship has surfaced, that being my lack of computational power needed for an appropriate simulation of interest to my mentor. Instead of a three-dimensional metrology simulation, I will most likely be restricted to two-dimensional simulation with my current computational resources. My mentor did mention to me that it may be possible to have me visit sometime in July to see some of the devices that I would have been working with, so that is something to look forward to.

Week 3: Getting Started with COMSOL

This week my mentor and I were able to find a way to get a license for me to download the COMSOL simulation software on my computer. This is a big step forward towards analysing our system of interest and it will be great to get experience using the software. With this software we hope to simulate a measurement using frequency modulated atomic force microscopy in the lab. At this time, this poses some difficulties due to his limited access to the lab and my limited access to computational power. I am going to limit the simulation to a two-dimensional surface, which is non-ideal because the measurement is attempting to image buried metal lines at varying depths. Also, the tip being used to measure the device is three-dimensional meaning we must find a way to generalize the tip-sample interaction in two-dimensions. Currently, I don’t have a good idea of how this will work because I don’t have access to the software yet.

Next week, I hope to learn more about using the COMSOL software so I can begin to conceptualize how we will tackle the issues at hand. Also, I am looking forward to the planned activities that the SPS committee has lined up for us. We have a professional networking workshop planned for Wednesday afternoon and our weekly hangout session which I have to look forward to as well. So far the experience of getting to know the other interns better and understanding how research at a national lab takes place has been enlightening. I know that the best has yet to come and I am excited to see what I will have to report next week.

Week 4: A Pattern Emerges

It is hard to believe that week 4 is over and essentially a month of the internship has passed. I have noticed a pattern with the way I structure my blog posts, I typically write a paragraph on how research related activities are going followed by a paragraph related to SPS committee activities. I don’t intend on changing this, so with that said, July is right around the corner and I hope that my project will start to gain some momentum this week. This should be the last blog I write about holding out for the COMSOL software license. My mentor sent me the receipt email and on Monday we will talk with the representative to get the license, finally! It is an expensive software and I am very grateful that he went out of his way to help me get access to it. Without it I am not sure, given the time constraints, that I would have had time to write this simulation from scratch with Python; although I had an idea after our first meeting of how I would do this. But, in my experience, ideas never go as smoothly as you expect when it comes to writing code.

In week 4, we had the great opportunity to listen to the career programs manager of APS, Midhat Forooq, give us a presentation on professional networking. I will take with me several tips she mentioned for expanding your professional network. She acknowledged that some people view meetings with your professional peers as somewhat robotic in nature, something I have experienced, but also noted that this doesn’t have to be the case. These are people that you may reencounter later in your career, and first meetings are sometimes awkward in any scenario, just try to make them as human as possible. This is not verbatim, but is how I perceived that particular tidbit in her presentation.

We received an updated version of our activities calendar and there are some things that I am really looking forward to, the dates are still tentative. On July 9th we have our virtual picnic, a nearly 3 hour event that our mentors can attend as well. I am sure there will be plenty of fun things planned and I am looking forward to it. On July 15th we will have a resume writing workshop, something that I will really appreciate. Every month or so, I will spend a day or two updating my resume and I put a lot of time and thought into how it is formatted and what I should include. I hope this workshop will clear up some of the questions I have had embarking resume writing on my own. On July 29th, we will have a virtual colloquium with Michael Fuhrer, someone who I have watched on YouTube several times. On YouTube, he has several talks on topology in condensed matter physics and solid state physics, both topics that have been relevant to me in my journey as an undergraduate researcher. Needless to say, I am excited to attend the colloquium to hear him speak.

Week 5: Halfway Mark

We are about at the halfway mark of this summer internship and it is hard to fathom, it seems like we only just started. From time to time I think about what it would have been like to have this internship in DC, but I am just happy that we were able to have the opportunity to still participate in this internship in some form. This past week, there were not any internship events to attend so there is not much to report on in that regard. Looking forward to this coming week we will have a colloquium as well as the virtual picnic to be excited about.

As far as research related activities go, I have officially downloaded COMSOL and have run some test simulations as practice. I started off by modeling the potential surface of a quadrupole in a box with appropriate boundary conditions. My mentor has also sent me some example scripts to look at modeling the vibrating cantilever over a silicon dioxide thin surface covering a silicon bulk surface. This week, I hope that we can meet to discuss the script and results from the script so I can hopefully take my own direction and add onto what he has already modeled.

Week 6: Hoping for Results

As week 6 is behind us, I am thinking about how much more I could have accomplished by this time if I were there in person. Considering that the research is mostly hands on experimental work, I imagine it would be much more. My hopes at the beginning of this internship was to work towards publishable results, but that doesn’t seem to be possible at this point. Communication during these trying times has been sparse, and as a result of this work is slow. My hopes for the remainder of this internship is that I can accomplish some kind of tangible results with COMSOL simulations, and have something presentable by the time we give our presentations.

This past week we weren’t able to hear Dr. Mather’s talk as planned, but I did get to meet several new people, talk about their work, and hear their advice for my future plans. I was telling one of the colloquium attendees about my interests in topological quantum computing, and she mentioned the Joint Quantum Institute near the University of Maryland. I have heard of this institution before, but it was interesting to hear what information she shared with me about it. The research done there is interesting and I will likely look more into it in the near future.

The week ahead we have a resume writing workshop, something that I will definitely take advantage of. One of the difficulties I have had with resume writing is keeping them short enough while including everything I think is important for employers and reviewers to know. I am confident that I will learn something practical through the workshop and be able to apply it to my resume writing skills in the future.

Week 7: How did it get late so soon?

7 weeks have passed, and that is truly hard to believe. Writing weekly blog updates has made me more aware about the passage of time, and how slippery it is. The main differentiatator of the weeks is the different speakers that we have the opportunity to listen to and interact with. This week, Dr. John Mather was able to join us for a Q and A type of session where he talked to us about his journey in Physics. It was inspiring to hear about how natural this field feels to him, and how he wouldn’t want to spend his time any other way. Something he said particularly that resonated with me is how he often is approached with people wondering about all the time he has dedicated to his work. To him, it isn’t work, it is something he would do even if it weren’t his job. More on the theme of time, he discussed the beginning of time as we know it, and how it really doesn’t exist in the way we might think. He told us how there is no definitive t₀, or time equal to zero, something I wish I had more time to inquire about. Since time is a dimension of spacetime, then did the universe really start from a zero dimensional point? From what I gathered, his answer would be no. He said there is no way to condense thre simensions of space, and one dimension of time into a single point, a notion that is really fascinating.

On the research front, I am spending most of my time learning and understanding the COMSOL software and the modules I was given access to. I managed to simulate a vibrating cantilever and ran simulations to determine its eigenfrequencies, or natural frequencies. From what I can tell, the software does this using boundary conditions and solving for a second-order differential equation using finite element analysis. Upon further searching, the free vibration of a cantilever is a fourth-order partial differential equation in space, and a second order ordinary differential equation in time. Solving with the appropriate boundary conditions give quantized modes of excitation which can be analysed in COMSOL. The next step is then to add a Platinum tip to the cantilever and see how it responds to varying electric potential surfaces.

Week 8 & 9: Topological Insulators

I decided to combine two blog postings into one this week because we didn’t have a speaker in week 8 and there wasn’t anything I would deem blog-worthy in that week. This past week we had a really interesting speaker, particularly for me because he spoke on topological insulators and their applications in modern computing. As an undergraduate, I spent a large portion of time trying to understand the role that topology plays in Physics, and naturally I have stumbled upon some of Dr. Fuhrer’s talks online. So when we were told he was going to be a guest speaker, needless to say I was quite excited to hear what he had to say. He explained the story of how Landau’s symmetry breaking theory was shown to be inadequate in describing all types of phase transitions of matter, and how the Quantum Hall effect exemplifies this inadequacy. Through some derivations of Landau levels, he showed us how this leads to quantized Hall resistance and the edge states that exist in the materials that exhibit this property. Something that interests me in the research that I have done is Majorana bound states and their application for information storage in quantum computers, a bit of a different route than Dr. Furher’s. I was curious after his talk on topological insulators if these bound states could exist in environments other than topological superconductors? Disregarding the possibility they may actually be fundamental particles of nature, the neutrino being a candidate for being Majorana-like fermions. Even though Dr. Furher wasn’t interested in the specific application of topological materials to quantum computation, it was still interesting to hear how him and the team at FLEET are planning to use them for more effecient transitors.