OFFICE HOURS | Professor Lena Kourkoutis Discusses Her Research

For this semester’s first installment of “Office Hours,” a series of interviews with prominent personalities on Cornell’s campus, Sunspots writer Gabriel Ares sat down for a chat with Applied Engineering Physics Professor Lena Kourkoutis. In the interview below, which has been edited for clarity, Kourkoutis talks about a range of topics, from electron microscopy–a technique that allows her to see the atomic structure of objects–to outreach to women in STEM.

There’s only a handful of people working in your field, and even fewer thinking about it at such an advanced level. So, to kick things off, can you tell us how you got into this field of study?

As a child, I was brought up to ask questions, and for me that goes from when you start playing with toys or looking at the sky, to research where you’re wondering how a battery works or how a biological object or a cell works. It’s connected. So I think I used to, as a child even, be interested in how things work.

I was fortunate enough to live in a family where my father was a physicist, so there was never a mental barrier for me. What so many people usually respond when they hear that you do physics is, “that sounds really hard,” but if you do it for a long time, physics doesn’t seem that hard anymore. There’s no real barrier. I think that’s something people really build up themselves. So, since I didn’t have that barrier, I was at the university a lot just seeing what people were doing. Then, when it came time to choose a major, which is actually before you go to college in Germany, I went down the list of all the majors that they had and started crossing things out. Initially, I didn’t want to do physics because of my father, right? I wanted to something different, but when I got to the end, that’s what was left. So I studied physics, which I really enjoyed, and then ended up in research.

What are you interested in or working on currently?

So, my group is really focused on using or understanding how a material, whether it’s an electronic device, battery, or a cell, works at the very microscopic level. We use electron microscopes that allow you to look at devices at the atomic scale and understand what makes them tick. It gives you a unique perspective on materials or really the world overall.

I’ll give you one example that we’re working on, more on the material side, which is the battery. If you think about your computers or phones or even an electric car, one of the biggest problems is the battery. We want your phone to not run out of power as we are running this interview, and we would like to be able to drive to Syracuse with an electric car, so we need really reliable batteries that last a long time. We are trying to understand why they fail and how we can design new types of batteries that are safer and have greater capacities.

And you’re doing this by using electron microscopy, or something more specific?

Electron microscopy is the big field and we just developed special techniques in that field to look at an interface between a liquid and solid in a battery. Because typically your battery has a liquid electrolyte and an electrode that is solid, so studying those types of interfaces through a microscope is a challenge. Here at Cornell, we’ve developed a technique that lets us access those interfaces.

Could you tell us a little bit about how electron microscopy works?

So, Cornell actually has a very long history of electron microscopy. There have been research groups since, I need to look up the exact number, but the 50s or 60s, that have developed techniques in electron microscopy at Cornell. Today, we can actually shape a beam of electrons down to an atomic size, a beam that’s smaller than an atom. Imagine a standard light microscope that is used in biology class. It uses light to image your structure. The resolution of your image is really limited by the wavelength of light, and in the typical optical setup you can see on the order of a few hundred nanometers. That means if you want to look at the atomic scale, which is a thousand times smaller, you can’t use optics. If you want to see how every atom is sitting and how it’s acting in its environment you need to use waves that have much shorter wavelengths, like electrons. Electrons are waves too, but the resolution of current state-of-the-art electron microscopes are on the order of half an angstrom. This is well below the size of an atom or the spacing between atoms in a material, so you can look at how materials are built from the bottom up.

Picture of a silicon lattice imaged through an electron microscope. Each dot corresponds to a single atom.

So, without trying to get too technical, when you’re developing these techniques, what are you playing with or changing?

So in our research, which revolves around imaging the interactions at the interface between a liquid and a solid, the difficulty is really the liquid because an electron beam won’t travel very far in air. To use electrons for imaging you have to have the sample in vacuum so the electrons can actually travel to your sample. But the problem is when you put a liquid in a vacuum it will sublimate. So a biological object will collapse; if you put a battery in with a liquid electrolyte it will disappear, and so on. You can’t look at those structures unless you have a way to kind of stabilize that liquid, so we’re actually borrowing a technique that was developed in biology many years ago: you can very, very rapidly freeze a liquid. So fast that it doesn’t crystalize and instead becomes amorphous. It’s just frozen- imagine taking a snapshot of the cell or a battery, that face is just immobilized. And you can look at that.

The other part of the challenge is that you can’t put a full battery under the microscope– it’s too big. So, we have to find a way to reach the place we want to look at and make it thin enough that an electron beam can actually look through it, and so we have found a way of making very thin slices out of frozen batteries to study those interfaces under an electron microscope.

That’s very cool.

It has impact in a lot of areas much beyond batteries. Think about cancer. When cancer develops in the body, you have hard material and soft cells. So, a tumor, right? To understand what happens during tumor development, you have to find a way to look inside the tissue and get access to the interactions between the hard and soft materials, so we apply the same freezing techniques to understand cancer progression.

Ok, another fun question: do you have any favorite things to look at under the microscope? Just because they might be cool to look at?

Oh, I get excited about seeing almost anything. It’s funny because if you think about a crystal or just anything around you, when you put it in a microscope, suddenly you see it in a totally different way.

For example, actually, for an outreach activity I am a part of, we are building these optical microscopes that you play with on your own, and it’s supposed to teach the kids how you use a microscope and how you can actually magnify things with two lenses. One of the things I tested under the microscope at home was a poppy seed. Poppy seeds, if you think about it, what do they look like? They just look like little black dots, right? They are small. If you look at one with just an optical microscope you see that actually, they are corrugated structures on the surface. It’s almost like the surface of the moon. It’s beautiful, and you can actually build a microscope at home, yourself, to image that, right? So just an optical microscope is exciting because you can see the small structures your eyes don’t see by themselves. And so, if you think about electron microscopes, you can go one step further down and suddenly you see a crystal, like a hard material that is made up totally differently. The atomic structure is totally different. So all of that is really exciting.

Image of transistors under an electron microscope. There are billions of these in every microchip. The arrow labeled SiGe is pointing at the transistor gate. Each transistor is 22nm across. For reference, the size of your red blood cells are between 6,000 to 8,000 nanometers.

Did you know pretty quickly once you got to college that you wanted to do research or become a professor?

No, you don’t really know that. There’s a long path to it, but I definitely considered it. That’s partly because I’ve seen my father. He lived a pretty good life and was able to travel, do research, and teach, but I considered other options at every step of the way. If you look at my path, it looks like I knew what I was doing, but I didn’t and people don’t. Sometimes you just end up where you are by accident.

It goes back to my initial comment. I think you need to ask questions and you should get excited about many areas. I ended up in electron microscopy by accident and I love it.

So, speaking of the outreach stuff, as I understand it, you were recently given the CAREER award by the National Science Foundation and part of that goes toward work with the community.

Yeah, so, many people get the CAREER award because, it’s kind of an early career award designed to develop your research direction. That award I actually used for understanding these liquid/solid interfaces. So, it kind of fits what we discussed, particularly on batteries.

But another component of that award is that you need to have broad impact, that’s what NSF likes to hear, but what that means is that we reach out to people beyond just those that are interested in our topic. So I do quite a lot of outreach in different areas, but one of the things that I really feel strongly about and that kind of ties back to what I said in the very, very beginning is that I think that you need to get kids excited about things. You need to let them ask questions, right? So students in my group have actually developed an optical microscope that you can take apart and put together by yourself. It’s very simple, but it makes you understand how a lens focuses and how you can use two lenses to get higher magnification.

This kit that we are developing will go into the CCMR lending library. These kits are available online with detailed instructions and sheets to guide teachers through the content. But you can also just request the kit and it will be sent out across the nation.

That’s really cool. Has most of the outreach you’ve done stayed focused on educating kids about science?

Yes, absolutely. I think everyone kind of picks their area of interest. I feel that by high school many people have already decided whether they want to go [into STEM] or not, so I prefer to reach out to younger groups. But I think it’s really about where your excitement is.

And then of course I‘ve done a lot with Cornell during the summer, getting groups of prospective students and telling them what my research is all about. It’s really neat. I think you can get those students excited about what Applied Physics is all about. I also worked on Expanding Your Horizons – this is a conference for middle school girls that’s organized every year by grad students across the nation. We have one here and this year. I don’t know the exact number – they had around 400 girls, and I actually gave a talk there this year. I think there are a lot of outlets where you can hopefully motivate students to pursue science.

That’s cool. Since you’ve done a lot of outreach that involves inspiring young girls to pursue science, could you tell us a little bit about being a woman in STEM?

I have actually had very little bad experience as a woman in the sciences. I’ve grown up in a male-dominated environment and I’m comfortable in it. But that is not true for everyone. I didn’t talk about this when we were talking about outreach, but I work with a lot of support groups that are specifically focused on women. I mean, if you look at our department for example, the number of female students is relatively small and some of them really need a better support system. Many want to see women role models, so even if I don’t need it, I’m part of this group and can help organize things like the Women of Physics and Related Fields event that aims to bring our community together and provide that support system. I think it’s important. It’s important to get a diverse environment in any field, including physics, so we, as a department and as part of Cornell in general, are trying to get closer to 50-50.

In general, it is good to see female scientists, that they exist, and that you can be one of them, at any age. Some women need it. I didn’t need it, actually. I was never turned off by the fact that there were no women.

Do you feel that a lack of women in STEM is an international problem?

I think it’s a problem everywhere right now. I think it’s more that some people are better at not worrying about it too much or are not as affected, and others aren’t. So, I don’t think it was an issue of place. I’ll give you one example that I’ve experienced. Typically, I travel to conferences by myself, but I have a husband and kids. So, my husband accompanied me to one international conference. He attended the first reception and we stood next to each other.

Every single person that I didn’t know passed by and looked at his nametag but not mine. That is, until one of the biggest people in the field came in – he’s a very close friend and collaborator – and started talking to me, and suddenly everyone was paying attention. That was a very, very strong sign [of discrimination]. I always felt there was nothing going on, but then sometimes you have experiences like that where you really wonder. I actually just prefer to travel by myself now, but that should not be the right response. I mean, everyone should be respected the same, right? So, there are cases where you need to a watch out a bit.

So, any final words?

My recommendation to all the students is: explore what Cornell and Ithaca have to offer. It’s a unique place both from an education perspective, but also the people that come together. And don’t dig yourself too much into your specific little area. I think this is a time to broaden the horizons a bit and I think this is a great place for that.