W.J. Carr Lecture/Physics colloquium

Details

Category: Department News

Published: Tuesday, February 14 2017 11:30

The W. J. Carr Lecture Series on Superconductivity and Advanced Materials was established by Dr. James L. Carr ' 89, and attracts some of the best researchers in this field each year. This year's distinguished Lecturer is Dr. Stuart Parkin, Director of the Max Planck Institute of Microstructure Physics and Professor at the Institute of Physics of the University of Halle-Wittenberg. Parkin is a pioneer in the science and application of spintronic materials, and has made discoveries into the behavior of thin-film magnetic structures that were critical in enabling recent increases in the data density and capacity of computer hard-disk drives. For these discoveries, he was awarded the 2014 Millennium Technology Prize.

Prof. Parkin will present both a department colloquium and technical seminar. His colloquium will be presented on Tuesday February 28th at 4pm in room 1410 of the John S. Toll Physics Building.

Title: Beyond charge currents: spin and ion currents for future computing technologies

Abstract: The era of computing technologies based on charge currents is coming to an end after more than 40 years of exponential increases in computing power that have been largely based on shrinking devices in two dimensions. A new era of "Beyond charge!" will evolve over the next decade that will likely be based on several new concepts. Firstly, devices whose innate properties are derived not from the electron's charge but from spin currents and from ion currents. In some cases new functionality will arise that can extend charge based devices but in other cases fundamentally new computing paradigms will evolve. Secondly, devices will inevitably become three-dimensional: novel means of constructing devices, both from bottom-up and top-down, will become increasingly important. Thirdly, bio-inspired devices that may mimic the extremely energy efficient computation systems in the biological world are compelling. In this talk I will discuss possible spintronic and ionitronic devices and how they may lead to novel computing technologies.

Bio:  Professor Stuart Parkin's research interests include oxide thin film heterostructures, high-temperature superconductors, and, magnetic thin film structures and spintronic materials and devices for advanced sensor, memory, and logic applications. Parkin's discoveries in magneto-resistive thin film structures enabled a more than 1000 fold increase in the storage capacity of magnetic disk drives for which he was awarded the Millennium Technology Award from the Technology Academy Finland in 2014. Most recently, Parkin has proposed and demonstrated a novel storage-class memory device, "Racetrack Memory", that is an innately 3D solid-state device with the storage capacity of a disk drive but with much higher performance and reliability. Parkin's other major research interest is cognitive - bio-inspired materials - that could enable ultra-low power computing technologies. Parkin is a Fellow/Member of several Academies, including: the Royal Society (London), National Academy of Sciences (USA), National Academy of Engineering (USA), German National Academy of Science - Leopoldina, Royal Society of Edinburgh, Indian Academy of Sciences, and TWAS, the academy of sciences for the developing world. Parkin is the recipient of numerous awards and honors including, the American Physical Society International Prize for New Materials, the Europhysics Prize for Outstanding Achievement in Solid State Physics, and the American Institute of Physics (AIP) Prize for Industrial Application of Physics. Parkin has received Honorary Doctorates from RWTH Aachen, Eindhoven University of Science and Technology, University of Regensburg, and University of Kaiserslautern. Parkin received the IEEE Daniel E. Noble Award for his work on MRAM, the IUPAP Magnetism Prize and Neel Medal for outstanding contributions to the science of magnetism, the APS David Adler Lectureship Award, the von Hippel Award from the Materials Research Society, the Swan Medal of the Institute of Physics (London), the Millennium Technology Prize and an Alexander von Humboldt Professorship − International Award for Research (2014).

Dean Jayanth Banavar Named Provost at the University of Oregon

Details

Category: Department News

Published: Tuesday, February 14 2017 09:06

Jayanth Banavar, dean of the College of Computer, Mathematical, and Natural Sciences (CMNS) at the University of Maryland, has been named provost and senior vice president at the University of Oregon. Banavar will end his six-year tenure at UMD in July and a national search for his replacement will begin immediately.

Read more.

Stacked nanocrystals offer a new twist on handedness

Details

Category: Research News

Published: Monday, February 13 2017 12:17

Chirality is another name for the asymmetry that we see between our left and right hands. This handedness crops up nearly everywhere in nature, from galaxy spirals down to the quantum mechanical properties of fundamental particles. Life itself boasts some of the most well-studied examples of chirality, including DNA's famed helical staircase.

Recently, some scientists have turned their attention to chirality found in the inorganic world of rocks, minerals and other non-biological materials. University of Maryland physics professor Min Ouyang leads a team that has been working to control chirality in tiny inorganic arrangements called nanocrystals. Their goal is to understand how atoms can cooperate to form larger, superchiral objects, analogous to how assemblies of carbon atoms stack into DNA. To achieve this, the researchers developed a new recipe for both engineering and analyzing chiral nanostructures from the bottom-up. This research was published recently in the open access journal Nature Communications.

Ouyang, whose work has been inspired by biological chirality, sees this research as an exciting step, with applications to a broad range of inorganic structures with tunable chirality. "Our technique is general, and does not depend on the material we used," Ouyang says. "Using inorganic molecules, we could mimic natural assemblies, perhaps building a DNA-like strand from the ground-up and study its chiral dependent physical properties, step by step."

The recipe begins in a flask containing a carefully crafted solution of cinnabar and penicillamine, both of which are chiral and play different roles in guiding the growth of nanostructures. Cinnabar, a red compound found naturally in volcanos, is readily synthesized in the laboratory. Here, it acts as an atomic building block, seeding the growth of chiral lattices. The mercury and sulfur atoms that make up cinnabar line up according to the handedness of the initial seeds. Penicillamine, an organic drug molecule, provides a helping hand for guiding the larger cinnabar assemblies. Smaller bits of cinnabar take their cue from the penicillamine's orientation, left or right, and stack into even bigger shapes, eventually completing a full nanocrystal.

Such crystal growth techniques have been used before, but Ouyang's group modified the process so that they could, for the first time, independently manipulate chirality of both the atomic building blocks and the larger crystals.

The researchers assembled crystals that ranged in size from tens of nanometers to a few hundred nanometers—roughly the size of viruses. They adjusted both the final nanocrystal size and their handedness by tweaking the different growth conditions. To show that they could control chirality the team purposefully constructed other, non-chiral shaped nanocrystals, like rods and cubes.

Caption: Electron microscope images of achiral and chiral shapes. The dotted line on the right chiral nanostructures outlines the twists that are the visual signature for handedness. (Images from paper, courtesy of authors)Ouyang and his collaborators used complementary methods to measure the chirality of their nanocrystals. They employed a high-power electron microscope to take snapshots of their creations, providing the first direct image of cinnabar's handedness. The images (inset) show diamond-like crystals with a pronounced s-shaped line where the shape is twisting. This twist, left or right, is the visual signature of the final product's chirality. In the case of the non-chiral structures, no 's' is present.

The researchers also shined light onto samples and looked at how they responded. Using this standard probe, they saw that, as expected, asymmetric structures absorbed light waves according to their handedness. More importantly, they used the optical absorption measurement to monitor the chirality at each growth stage, from molecules to lattices to nanocrystals. To complete the study, the team developed a mathematical model for understanding this observed chiral evolution, one that was adaptable to the different length scales.

Taken together, Ouyang and colleagues have demonstrated a powerful method for systematically examining nanoscale chirality, which includes flexible synthesis, direct visualization, and a tested computational tool. Bottom-up experiments, like this work, may enable a better understanding of chirality in inorganic materials, such as those used for novel quantum spin-based technologies.

Anlage Named Finalist for Invention of the Year Award

Details

Category: Department News

Published: Wednesday, February 08 2017 11:25

Prof. Steven Anlage's work on time reversed waves in chaotic systems has spun off a new wireless power transfer technology which has been chosen a finalist in the Physical Sciences Category for the UMD 2016 Invention of the Year Award. Winners will be honored at Innovate Maryland: Celebration of Innovation and Partnerships sponsored by the Division of Research, Office of Technology Commercialization, Corporate Connect Council, MTech, and the Academy of Innovation & Entrepreneurship. The event is scheduled for Wednesday, April 12, 2017 at 4:30 pm, at a soon-to-be announced venue.

Anlage's three inventions are a Method of Delivering Power to a Moving Target Wirelessly via Electromagnetic Time Reversal, Selective Collapse of Nonlinear Time Reversed Electromagnetic Waves, and Dual-Purpose Rectenna with Harmonic Generation for Wireless Power Transfer by Nonlinear Time-Reversal.

Each year, UMD honors exceptional inventions that have the potential to make an important impact on science, society, and the free market. The Invention of the Year award nominees come from three categories: Physical Sciences, Life Sciences, and Information Sciences. One invention from each category is selected to win the Invention of the Year Award.