The Materials Universe Podcast – Season 2 Episode 1 – The Quantum Pancake

[00:00:00] Bailey Tibbett: Welcome to the Materials Universe podcast, where we will explore the materials world and how it shapes our lives. My name is Bailey Tibbett, and I will be your host this season. Please join me as I interview researchers from the Center for Dynamics and Control of Materials at the University of Texas at Austin.

Hello and welcome. You’re listening to the Materials Universe podcast, and today with me, I have Dr. Elaine Lee, who is a professor of physics at the University of Texas at Austin. Welcome, Dr. Lee. Yay.

[00:00:31] Dr. Elaine Li: Thank you.

[00:00:33] Bailey Tibbett: So to start, tell me a little bit about what you do at UT Austin and how you kind of found yourself.

at this university?

[00:00:41] Dr. Elaine Li: Well, I’m an experimentalist. I mainly use laser in terms of spectroscopy to study a variety of materials. And I joined UTS in 2007. So I’ve been here for a while now.

[00:00:53] Bailey Tibbett: Wonderful. I guess for those listeners who may not be as familiar with the field of material science, could you explain its importance in a couple innovations that it might have enabled in like a couple sentences or so?

[00:01:05] Dr. Elaine Li: Right. I think I’ll come back to this and I would like to say everything is made of something. Yes. So material science is really foundational. And whenever you want to make an innovation in technology, you think about what this technology is made of and how we make the materials better. You know, example will be clean energy and public health and certainly information technology.

So in all of this area, material is the starting point how you improve existing technology. And I’m happy to elaborate on a particular area that’s relevant, you know, for example, to the MRSEC research we’re doing.

[00:01:46] Bailey Tibbett: Yeah, I think that would be wonderful.

[00:01:48] Dr. Elaine Li: Okay, so the MRSEC, this is the second round that UT has received this prestigious NSF funded award.

In this round, I’m involved in the IRG named Tomale Thin Hydrostructures. The idea is really control material property with atomic precision. In this particular case, we’re actually thinning down material to a unit cell thickness. So you cannot make material that’s thinner. Why a thin material is important.

You know, for example, we can imagine future electronics are built on the walls or a wearable. All of these application will require ultra light materials. So this is Where the material we’re working on could be relevant for future technology. Another very important example is in semiconductor chip technology.

So we all know semiconductor chip is foundational to all of the electronics devices we’re using. And the building block of these semiconductor devices is called transistor. So transistor is essentially a switch. And right now we’re switching electrons from what’s called between the source and drain and the channel between them is already down to three nanometer in the most advanced technology.

[00:03:02] Audrey Colegrove: Hi guys, my name is Audrey and I’m a producer here at the Materials Universe. I’m just popping in to give you a little bit more information. So what is a semiconductor? Let’s break it down. Semiconductors are materials that have an electrical conductivity somewhere between highly conductive materials like metals and non conductive materials or insulators like rubber.

One of the most common examples of semiconductors would be silicon. You can find it in most of our technology, like the device you’re using to listen to this podcast. Like Dr. Li said, semiconductors can sometimes conduct electricity and sometimes not, which makes them act almost like a tiny light switch but for computer chips.

[00:03:38] Dr. Elaine Li: And as the devices shrink in lateral dimension, they also need to get thinner. And again, atomically thin thickness is the ultimate limit you can get to. So we’re really pushing the boundary of that technology.

[00:03:51] Bailey Tibbett: Wow, that’s so cool. I guess more broadly than what kind of drew you to focus on your research areas in your lab specifically.

[00:04:00] Dr. Elaine Li: So I’m a professor in the physics department. So I like to think about the broader impact of my research is really in information technology. And now we have to talk about what are the key component for information technology. To me, there are three key components. One is how do we store information, second is how do we process information, and third is how we transfer information.

Information are stored in these magnetic material, that’s like little fridge magnet. So information we use today are stored in a binary form, they’re represented with zero and ones in a computer. And imagine you have a fridge magnet with a snorkel pole pointing up, that would be called a fridge magnet. A bit one, if they’re pointing down, that will be called bit zero.

So the technology is so advanced, each of these little bits is only like a 10 nanometer across in its lateral size. And then while you’re reading these informations, magnetic storage devices is already very advanced. So there, you’re running into the worry that these bits of magnet become unstable. If you shrink them further, so this is one area that material has magnetic property can push that information storage technology.

Second part is information processing. As we talked about, it involves a lot of processing. Binary information, change it from zero to one and do logical operations. And there we use transistors. And third aspect is information transfer. The bulk of the material information transfer, especially long distance information transfer are done through laser pathing through fibers.

So what we work on is not immediately going to be on the market, but we ask very fundamental questions. What is the smallest bit of material that we can use to store information, to process information, and to transfer information? So that’s the foundation, that’s the frontier, scientific frontier we’re pushing towards.

[00:05:59] Bailey Tibbett: Okay, that’s so amazing. I guess on that front then, are there any like particular hypotheses that your lab is investigating that you’d like to share?

[00:06:08] Dr. Elaine Li: Yeah, so, you know, for example, we want to ask the question, is it possible to control the smallest bit of magnet? And that would be a single electron or a single, what we call a single hole.

It’s a missing electron. An electron has this bizarre property called spin. There’s no classical analog. So you can think about the spin essentially like a little magnet, right? And you cannot get a particle that’s smaller than an individual electron to carry that spin and to store information. So this is one aspect we’re trying to ask.

Can we confine, find a material that allows us to isolate individual electrons that we can manipulate the orientation of the spin of that electron? Right. That’s one aspect we’re pushing. The second is what are the smallest semiconductor structure we can use so we can actually perform a larger gate on these binary informations?

And finally, can we transfer information using the smallest pocket of light? That’s a single photon. So my research program touches on all that aspect of, you know, the quantum limit of information technology.

[00:07:18] Bailey Tibbett: Wow, that’s so amazing. I know I keep repeating that, but it’s just so cool thinking about things in their basic unit.

In a similar vein, do you have any areas of your research that you feel need expansion on? Or how do you move from each topic of research? How do you choose from each?

[00:07:36] Dr. Elaine Li: Uh, you know, really a lot of my research is motivated by innovations in material science, I would say. You know, I think the overall scheme is really pushing the quantum limit.

You know, I think this is related to both our research scheme in this particular IRG. Control material property down to the single atomic layer thickness. These material can be used to confine individual electrons, which can be used to store information in the smallest possible way, smallest bit of matter.

And it can be used for processing information, making smaller transistors, materials, and they can be built in future transistors. And then finally, emitting single photon at a time. And I like to say, you know, sometimes academic research tend to be a little bit far away from practical application. In the particular area that we’re working on, atomic thin semiconductor, they’re actually on the roadmap of a lot of major semiconductor company around the world.

They really think this material eventually will make it to large scale transistor technology we’re currently using.

[00:08:43] Bailey Tibbett: Okay, so it’s becoming kind of more mainstream online?

[00:08:46] Dr. Elaine Li: There are definitely companies that are investing in how to make these materials on the scalable, using the scalable matter and technology.

[00:08:53] Bailey Tibbett: Are there any materials that your lab is studying specifically that you think are promising?

[00:08:59] Dr. Elaine Li: Right, so not just my own group, there’s many research groups around the world that are studying these atomally thin material that are called transition metal dichotinide. It’s a form of semiconductor. One example will be maladonin disulfide.

So it is investigated by the semiconductor company as a building block of their transistor. But our interest is really manipulate them in the unconventional way. And I think, uh, prior speakers at this podcast have talked about quantum dots. You know, you can imagine taking a thin sheets of material, like a piece of paper, and then rotate them relative to each other.

And two pieces of paper are coupled in an electronic way. And then they can further create these, I like to call them quantum pancake. And then they’re defined as little bits of units that are confining individual electrons. And sometimes this individual electron can be coerced. To talk to each other and or form a larger scale of order matter, and they can be used in some ways that people imagine them as quantum simulator solving some complex physics problem that no classical computer can effectively solve.

So there are just many ways that the simple material building block can push the frontier of technology and particularly quantum technology. Yeah, please tell me if I’m using too many jargons that it’s hard to No, I

[00:10:23] Bailey Tibbett: think this is wonderful. I love the idea of a quantum pancake. It sounds delicious.

[00:10:27] Audrey Colegrove: Quantum superlattices are structures composed of alternating layers of two or more materials. These lattices are typically on the nanometer scale, and I’d be pretty impressed if you could see that with your naked eye. So let’s consider something visible in our everyday lives. Kitchen strainers come in a huge variety of shapes and sizes with different purposes.

Strainers with larger holes are meant for washing produce and letting the dirt drain out, while finer mesh sieves can help strain particles out of broth or oil. The layers in quantum superlattices are similar to these strainers, but instead of being millimeter thin, Thick. They are nanometers thick. To take our visualization even further, you could say quantum super lattice are like if you layered your kitchen strainers together so that the different layers worked to catch specific things, except instead of food or dirt, they catch particles like electrons or light.

[00:11:16] Dr. Elaine Li: It’s a rail of them. So we’re trying to either individually pick out electron or control the electron can find one of these little pancake where we can see. Can the electron hop around and then couple to each other, form some exotic state?

[00:11:32] Bailey Tibbett: What techniques do you use to study the properties of these materials?

[00:11:35] Dr. Elaine Li: Optical technique. Yeah, right. So you can imagine, you know, actually there’s a fundamental challenge when we use optical method to study these little quantum pancake is, um, for the most exotic property, this little quantum units has a size about 10 nanometer. But most of the time our laser beam is on the order of a micron.

So that’s a hundred times larger than the individual unit. So we do are left with a lot of puzzles sometimes when we measure something from thousands of these quantum pancake, can we associate them with individual one? How do we relate? are experimental, observable to how these individual entity of electrons or individual spins are behaving.

So that is a challenge that is a puzzle we solve in a laboratory all the time, but we love puzzles as scientists. So that’s been a lot of fun.

[00:12:26] Bailey Tibbett: Yeah, of course. I think this is kind of switching topics a little bit, but we’ve heard from some of yours. Students that you describe your role at UT Austin as like the perfect job due to the balance between kind of teaching and then also like researching into these subjects, how do you manage to integrate this into your lab effectively?

And I guess, like, what are some challenges you face when you’re trying to balance Teaching your students, mentoring, guiding them, and then also pushing forward in research.

[00:12:53] Dr. Elaine Li: Right, so I think my teaching role are, you know, divided into two different, very different aspects. Undergraduate teaching in a classroom and also graduate teaching in a research environment.

So if we’re talking about teaching graduate students doing research, I really think that’s, you know, I’m, A coach, I’m coaching them to how to pursue original research, right? I have to say, I’ve been working with a really amazing student at UT Austin. I just, they inspire me and you know, they are motivated, working hard, coming out with uh, interesting results.

And we always have to. Go through many iteration of discussion, and oftentimes my role is just to ask questions. I look at their result and ask questions, and I give them some guidance in terms of where they might be able to find the answers. And sometimes we engage collaborators. I’m really there to facilitate, I would think, that’s my role.

And that’s been a lot of fun. They taught me a lot. new physics and we make discoveries together. And then of course there’s the teaching in the classroom. So in classroom I’d be mostly teaching a lot of introductory courses to engineering students. So in that, one of my favorite class to teach is Maxwell equation.

And that’s because that describe how light behave and that it’s intimately related to my research. And. You know, I can never get tired of those equations because the four little equation describes so much that’s relevant to our daily life. So I enjoy teaching that role as well. So when it comes to balancing, of course, uh, there’s always a constraint on everybody’s available time, right?

So I would only think about what my student can do independently, where do they really need my help? So I prioritize those tasks that they really need me. And I also try to make communication with, for example, with my graduate student easy in the sense that, you know, we use a different app, they can find me during other hours or when I’m traveling.

So we just try to make it efficient and be flexible and work with each other in that way.

[00:14:54] Bailey Tibbett: That’s so cool. I think, um, yeah, it’s kind of crazy. I remember back in my beginning engineering classes, learning about like these fundamental equations or constants, and then you kind of just see them everywhere.

It’s like when I learn a new word. All of a sudden, I hear that word like in every single place, like it’s the most common word all of a sudden, even if it’s the most obscure one. Yeah,

[00:15:12] Dr. Elaine Li: that’s the beauty of fundamental science. They’re really at the foundation of everything that’s around us and all technologies.

[00:15:18] Bailey Tibbett: I’ve heard that you’ve been appointed as the new co director of the Quantum Institute. Can you tell me a little bit about the research direction that you’d like to go that way?

[00:15:25] Dr. Elaine Li: Right. So that’s the Texas Quantum Institute. And the kickoff of that institute is really just. in April this year, we’re quite excited for this institute for the reason that UT has been needing this institute as umbrella organization for various quantum research on campus.

You know, for example, UT Merced that we’re both associated with is one aspect of quantum research in the material science, but there’s this other aspect, Texas Quantum Institute, I’ll call them TQI going forward, have identified four area of strength for UT’s research in quantum area. That includes quantum algorithm, quantum material, quantum metrology, and quantum devices and quantum systems.

Right? So, you know, these are the area that UT are home to many of the world leading researchers, and that’s the area we hope to make the biggest impact. The institute is very new. What function am I serve at UT has yet to be fully discovered and developed and established, but we’re very excited to have this umbrella institute that allow us to either collaborate with other institute, federal agency, or state government in ways that it’s difficult to do prior to the formation of this institute.

[00:16:41] Bailey Tibbett: Oh, that’s so cool. So it’s kind of like an institute that’s helping a lot with the collaboration of different subjects.

[00:16:46] Dr. Elaine Li: That exactly is the goal. We also there are few near term activity we have either implemented or have planned. And I give you some examples. So one of the program that we have already implemented is called the TQI research fellow.

So they provide fellowship to either post postdoctoral researchers or graduate students. And the idea is these students and fellows are going to be co supervised. By more than one advisors, and they’re going to be the catalyst of cultivating collaborative research. It’s not, you know, the scope of the research go beyond what UT Merced cover.

And so these are again, you always want to support your young people, and they are the one who make things happen. So we’re very excited to have selected the first cohort of fellow. We’re looking forward to work with them and build a stronger, more integrated quantum community at UT. That’s one example.

And the other example is what we have an ambition to establish a nationally recognized facility that we call metrology facility. So what is metrology? Metrology is about accurate measurement, right? So this metrology can be used in variety of technologies that include semiconductor or the future quantum technology.

It means how do I Yeah. Perform measurement to understand the device I’m building. So there is, I can see there’s a gap between academic research and industry in many cases. I’ll use semiconductor industry as an example, because that’s the area that I’m more familiar with. So the devices I talked about, semiconductor transistor, they’re so advanced, they’re literally a thousand steps.

Industry that people used to build these advanced devices, any step has a failure that could lead to the failed the final product. So a huge challenge the industry phase is really a low yield for their most advanced chip. So there the academic can really help and invent new tools. To monitor this process, and monitor the device they’re fabricating every step along the way, so to improve the yield.

So I feel this is an area, metrology is an area, the academic and industry can really effectively collaborate. So there was, uh, a report, initiate, you know, release by NIST, I think they stand for National Institute of Science and Standard Technology. So they identify what’s called the mitology gap as what is critically needed for chip technology in the country.

So we have the ambition to establish the shared facility to help with that, to fill that mitology gap.

[00:19:27] Bailey Tibbett: I know you kind of touched on this, I guess, but as the new co director of the Institute and then also the director of the IRG II for our university’s MRSEC, we can move on to our final question, which is, how do you think material science will have an impact on the newest emerging trends in technologies?

Like, what do you think material science can provide for them?

[00:19:49] Dr. Elaine Li: Right. So, Material science foundational, everything is built of something. And I just want to give some examples, right? So, you know, one example is what we call quantum sensing, and you can think about one version of quantum sensing as a new version of MRI technology.

MRI stands for magnetic resonant imaging. It’s very broadly used in healthcare, for example. So they actually are. build on how human body interact with nuclear spins. And then the next version is really, can we make it more sensitive? Maybe we can make them to interact with the electron spin. And also these atomic thin material we’re developing can be the host for these electron spins.

We can place them closer to the organ or whatever thin material that we want to You know, entity that we’re trying to sense and really imagine a new iteration of imaging technology that will make an impact in health, right? And of course, I have not touched on energy. That’s because UT has its own entity.

Just to tackle that challenge, we have the Energy Institute. Right? Material science, innovation and material science is instrumental for clean energy and climate science. Climate science can also benefit from, for example, quantum sensing. UT has a new center funded by NASA to do exactly that. So they want to put sensitive quantum sensor into space missions, so they can actually monitor mass motions on the planet, on Earth, and then inform policymakers what to do with that information.

So I would say, Quantum science, quantum technology promoted by material science progress is going to have broad impact in all of this area, health, clean energy, climate science and information technology, you name it. Any technology sector, I think material science will be, play a major role in innovating these technologies.

[00:21:46] Bailey Tibbett: That makes sense. I mean, it’s like you said, everything has to be made of something, right? I guess if there’s one thing that you want our listeners to take away from listening to this episode of the podcast, what would that be in terms of material science?

[00:21:59] Dr. Elaine Li: I really hope more young people join us. You know, I think we live in a age that is so influenced by social media.

We need more of these podcasts, or maybe TikTok videos to encourage young people to join this effort. You know, because it’s foundational to progress in technology. And there are just many challenges in the world we face today, you know, associated with clean energy, healthcare, of course climate. And We need more young people to join in the effort in science and technology innovation.

And it’s really cool. And it’s, uh, I’ve never had a boring day at work.

[00:22:37] Bailey Tibbett: That’s wonderful. That’s always good to hear. I feel like not very many people can say that. So yeah, hopefully the idea of a quantum pancake will help to bring in fresh people.

[00:22:47] Dr. Elaine Li: Yeah, they’re hosts for this individual quantum entities that really represent the next quantum leap of technology.

[00:22:54] Bailey Tibbett: Yeah, well, I think you’re a very inspiring researcher. So just hearing about you talk about your work has been wonderful. And I really appreciate you taking the time to be on this.

[00:23:02] Dr. Elaine Li: Well, thank you very much for having me here.

[00:23:05] Bailey Tibbett: That’s all for today’s episode of the Materials Universe podcast. Thank you for listening to our interesting conversations with inspiring guests from different fields of science and engineering.

We hope you enjoyed learning something new. Please leave us a review and share this podcast with friends. You can follow us on social media at Texas CDCM on Instagram and X. Thank you to the National Science Foundation and the University of Texas at Austin. And an additional thank you to the LAITS Audio Studio crew for their help with the production of this podcast.