Department of Applied Physics and Materials Science - Materials Science

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Highlights

Light as a Feather, Stiffer Than a Board

11-18-11

Julia R. Greer, Assistant Professor of Materials Science and Mechanics, and colleagues have developed the world’s lightest solid material, with a density of 0.9 milligrams per cubic centimeter. The new material, called a micro-lattice, relies, on a lattice architecture: tiny hollow tubes made of nickel-phosphorous are angled to connect at nodes, forming repeating, asterisklike unit cells in three dimensions. "We're entering a new era of materials science where material properties are determined not only by the microscopic makeup of the material but also by the architecture of the constituents," Greer says. [Caltech Feature]

Tags: APhMS research highlights Julia Greer

Using DNA to Manufacture Nanoscale Devices

11-16-11

William A. Goddard III, Charles and Mary Ferkel Professor of Chemistry, Materials Science, and Applied Physics, has received $1.25 million from the National Science Foundation (NSF) to develop a process that takes advantage of DNA's talent for self-assembly to arrange nanomaterials such as carbon nanotubes and proteins into configurations designed for use in devices such as sensors, transistors, and optical components. [Caltech Feature]

Tags: APhMS research highlights health William Goddard NSF

An Incredible Shrinking Material

11-07-11

Graduate student, Chen Li, and colleagues including Brent Fultz,  Professor of Materials Science and Applied Physics, have shown how scandium trifluoride (ScF3) contracts with heat.  "A pure quartic oscillator is a lot of fun," Professor Fultz says. "Now that we've found a case that's very pure, I think we know where to look for it in many other materials." Understanding quartic oscillator behavior will help engineers design materials with unusual thermal properties. "In my opinion," Fultz says, "that will be the biggest long-term impact of this work." [Caltech Press Release] [Nature Article]

Tags: APhMS energy research highlights Brent Fultz Chen Li

Using Laser Light to Cool Object to Quantum Ground State

10-07-11

Oskar J. Painter, Professor of Applied Physics and Executive Officer for Applied Physics and Materials Science, and colleagues including graduate student Jasper Chan have cooled a miniature mechanical object—a tiny mechanical silicon beam— to its lowest possible energy state using laser light. The achievement paves the way for the development of exquisitely sensitive detectors. "In many ways, the experiment we've done provides a starting point for the really interesting quantum-mechanical experiments one wants to do," Painter says. [Caltech Press Release]

Tags: APhMS energy research highlights Oskar Painter Jasper Chan

Nano-mechanics of Carbon Nanotube Research Wins Art Competition

08-22-11

Siddhartha (Sid) Pathak, a W. M. Keck Institute for Space Studies (KISS) Postdoctoral Fellow in Material Science, has received the first prize in the NanoArt 2011 International Competition. The inspiration for Dr. Pathak's entry entitled "In-situ SEM deformation of CNT micro-pillars" is his research on nano-mechanics of carbon nanotubes.  As a KISS postdoc Dr. Pathak is working with  Professor Julia Greer on mechanical testing of carbon nanotubes at submicron length scales, with a particular emphasis towards space applications.  

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Tags: APhMS energy research highlights Julia Greer KISS Siddhartha Pathak postdocs

Disorder Is Key to Nanotube Mystery

08-12-11

William A. Goddard III, Charles and Mary Ferkel Professor of Chemistry, Materials Science, and Applied Physics; and Posdoctoral Scholar Tod Pascal believe to have solved the mystery of why water spontaneously flows into extremely small tubes of graphite or graphene, called carbon nanotubes.  Using a novel method to calculate the dynamics of water molecules they have found that entropy is the missing key.  "It's a pretty surprising result," says Professor Goddard "People normally focus on energy in this problem, not entropy." [Caltech Press Release]

Tags: APhMS energy research highlights William Goddard Tod Pascal

Engineers Solve Longstanding Problem in Photonic Chip Technology

08-04-11

Liang Feng, a Postdoctoral Scholar in Electrical Engineering who works with Professor Axel Scherer, has designed a new type of optical waveguide - a 0.8-micron-wide silicon device. The waveguide allows light to go in one direction but changes the mode of the light when it travels in the opposite direction. This new technique to isolate light signals on a silicon chip, solves a longstanding problem in engineering photonic chips. [Caltech Press Release]

Tags: APhMS EE energy research highlights Liang Feng Axel Scherer postdocs

One-way Transmission System for Sound Waves

07-26-11

Postdoctoral scholar, Georgios Theocharis, and GALCIT alumnus Nicholas Boechler; working with Professor Chiara Daraio, have created the first tunable acoustic diode- a device that allows acoustic information to travel only in one direction, at controllable frequencies. [Caltech Press Release]

Tags: APhMS energy research highlights Chiara Daraio GALCIT Georgios Theocharis Nicholas Boechler postdocs

Converting Heat into Electricity in Space and on Earth - High-Performance Bulk Thermoelectrics

05-23-11

Jeff Snyder, Faculty Associate in Applied Physics and Materials Science, and colleagues have developed a thermoelectric material that might be able to operate off nothing more than the heat of a car's exhaust. "You'll see applications wherever there's a solid-state advantage," Snyder predicts. "One example is the charging system. The electricity to keep your car's battery charged is generated by the alternator, a mechanical device driven by a rubber belt powered by the crankshaft. You've got friction, slippage, strain, internal resistance, wear and tear, and weight, in addition to the mechanical energy extracted to make the electricity. Just replacing that one subsystem with a thermoelectric solution could instantly improve a car's fuel efficiency by 10 percent." [Caltech Press Release]

Tags: APhMS energy research highlights Jeff Snyder

Experiments Settle Long-Standing Debate about Mysterious Array Formations in Nanofilms

05-19-11

Sandra M. Troian, Professor of Applied Physics, Aeronautics, and Mechanical Engineering, and colleagues' experiments have confirmed which of three possible mechanisms is responsible for the spontaneous formation of three-dimensional (3-D) pillar arrays in nanofilms (polymer films that are billionths of a meter thick). "My ultimate goal is to develop a suite of 3-D lithographic techniques based on remote, digital modulation of thermal, electrical, and magnetic surface forces," Troian says. Confirmation of the correct mechanism has allowed her to deduce the maximum resolution or minimum feature size ultimately possible with these patterning techniques. [Caltech Press Release]

Tags: APhMS research highlights GALCIT MCE Sandra Troian