Department of Applied Physics and Materials Science - Applied Physics

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Highlights

Microstructures Self-Assemble into New Materials

03-03-20

A new process developed at Caltech makes it possible for the first time to manufacture large quantities of materials whose structure is designed at a nanometer scale—the size of DNA's double helix. Pioneered by Professor Julia R. Greer, "nanoarchitected materials" exhibit unusual, often surprising properties—for example, exceptionally lightweight ceramics that spring back to their original shape, like a sponge, after being compressed. Now, a team of engineers at Caltech and ETH Zurich have developed a material that is designed at the nanoscale but assembles itself—with no need for the precision laser assembly. "We couldn't 3-D print this much nanoarchitected material even in a month; instead we're able to grow it in a matter of hours," says Carlos M. Portela, Postdoctoral Scholar. "It is exciting to see our computationally designed optimal nanoscale architectures being realized experimentally in the lab," says Dennis M. Kochmann, Visiting Associate. [Caltech story]

Tags: APhMS research highlights GALCIT MCE Julia Greer Dennis Kochmann postdocs Carlos Portela

How Electrons Break the Speed Limit

12-10-19

Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, and Jinjian Zhou, Postdoctoral Scholar, have developed a way to predict how electrons interacting strongly with atomic motions will flow through a complex material. "Using a new method, we have been able to predict both the formation and the dynamics of polarons in strontium titanate. This advance is crucial since many semiconductors and oxides of interest for future electronics and energy applications exhibit polaron effects," says Bernardi. [Caltech story]

Tags: APhMS research highlights Marco Bernardi postdocs Jinjian Zhou

Best Paper Award

10-30-19

Postdoctoral Scholar Carlos M. Portela, working with Professor Julia Greer and Dennis Kochmann, has won the Gold Paper Award. The title of the paper is "Supersonic Impact on Carbon Nano-architected Materials." The award was granted to the best student contribution across all topic areas at the Society of Engineering Science (SES) 56th Technical Meeting.

Tags: APhMS honors Julia Greer Dennis Kochmann postdocs Carlos Portela

Levitating Objects with Light

03-18-19

Ognjen Ilic, postdoctoral scholar in Professor Harry Atwater’s laboratory, and colleagues have designed a way to levitate and propel objects using only light, by creating specific nanoscale patterning on the objects' surfaces. "We have come up with a method that could levitate macroscopic objects," says Professor Atwater, who is also the director of the Joint Center for Artificial Photosynthesis. "There is an audaciously interesting application to use this technique as a means for propulsion of a new generation of spacecraft. We're a long way from actually doing that, but we are in the process of testing out the principles." [Caltech story]

Tags: APhMS research highlights Harry Atwater postdocs Ognjen Ilic

Microscopic Devices That Control Vibrations Could Allow Smaller Mobile Devices

12-12-18

Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed phononic devices that include parts that vibrate extremely fast, moving back and forth up to tens of millions of times per second. The devices were developed by creating silicon nitride drums that are just 90 nanometers thick. The drums are arranged into grids, with different grid patterns having different properties. Professor Daraio, along with former Caltech postdoctoral scholar Jinwoong Cha, have shown that arrays of these drums can act as tunable filters for signals of different frequencies and can act like one-way valves for high-frequency waves. [Caltech story]

Tags: research highlights Chiara Daraio MCE APh postdocs Jinwoong Cha

President Rosenbaum Highlights Postdocs as "Unsung Heroes"

09-24-18

In a letter to the Caltech community during National Postdoc Appreciation Week, the Caltech President emphasizes the role this key group plays at the Institute. He stated, “Caltech's mission of world-leading research and education depends crucially on our postdoctoral scholars. Although their time at Caltech may be short, they quickly become vital parts of the Institute's intellectual fabric.” [President’s Letter] [EAS Postdoc Resource Page]

Tags: APhMS EE GALCIT MedE MCE CMS ESE Thomas Rosenbaum postdocs

No Motor, No Battery, No Problem

05-15-18

Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed robots capable of self-propulsion without using any motors, servos, or power supply. Instead, these first-of-their-kind devices paddle through water as the material they are constructed from deforms with temperature changes. "Combining simple motions together, we were able to embed programming into the material to carry out a sequence of complex behaviors," says Caltech postdoctoral scholar Osama R. Bilal, who is co-first author of the PNAS paper is titled "Harnessing bistability for directional propulsion of soft, untethered robots." [Caltech story]

Tags: research highlights Chiara Daraio MCE APh postdocs Osama Bilal

Solving Pieces of the Genetic Puzzle

05-09-18

Postdoctoral scholar Nathan Belliveau working in the laboratory of Professor Rob Phillips has applied a method called Sort-Seq to mutate small pieces of noncoding regions in E. coli and determined which regions contain binding sites. Binding sites are the locations where specialized proteins that are involved in transcription—the first step in the process of gene expression—attach to DNA. "Humans have such a wide variety of cells—muscle cells, neurons, photoreceptors, blood cells, to name a few," says Professor Phillips. "They all have the same DNA, so how do they each turn out so differently? The answer lies in the fact that genes can be regulated—turned on or off, dialed up and dialed down—differently in different tissues. Until now, there have been no general principles to help us understand how this regulation was encoded." [Caltech story]

Tags: research highlights Rob Phillips APh postdocs Nathan Belliveau

Postdoctoral Scholar Receives Dissertation Award From American Physical Society

12-10-14

Moureen C. Kemei, Resnick Sustainability Institute Prize Postdoctoral Scholar in Applied Physics & Materials Science, has recieved the American Physical Society's Richard L. Green Dissertation Award in Experimental Condensed Matter or Condensed Matter Physics. The award recognizes her outstanding thesis on "Magnetostructural and Magnetodielectric Coupling in Spinel Oxides" citing her achievement in employing advanced characterization tools to gain new insights into the structure and electronic properties of magnetic materials and solid oxide fuel cell (SOFC) cathode materials. The exploration of SOFC cathode materials is the focus of Moureen’s research at the Resnick Sustianability Institute, which she works on in the lab of Professor Sossina Haile. [Dr. Kemei’s Dissertation]

Tags: APhMS honors energy Sossina Haile Moureen Kemei postdocs

Former Caltech Postdoc Receives Israel Prize

01-15-14

Mordechai (Moti) Segev, a former postdoctoral fellow in Professor Amnon Yariv's group, will be receiving the Israel Prize for Physics and Chemistry. Dr. Segev is receiving the prize for ground-breaking research in the field of optics and lasers. "I am naturally proud of the achievements of former students and postdocs who started their scientific career in my group," says Professor Yariv. "Among this group Moti has become, in the relatively short time since leaving us, one the best known and influential scientists in the world in the field of quantum electronics and its amazing offspring of nonlinear optics. I am looking forward to a continuing stream of intellectual and experimental innovation flowing from him and his research group at the Technion."

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Tags: Amnon Yariv APhMS honors energy research highlights Moti Segev postdocs