Spring 2020

Shining Light on Magnetism: Controlled Magnetic Switching With Ultrafast Optical Pulses

Eric Fullerton
Friday, February 7, 2020 - 11:30am

The possibilities of manipulating magnetization without applied magnetic fields have attracted growing attention over the last two decades. The low-power manipulation of magnetization, preferably at ultra-short time scales, has become a fundamental challenge with implications for future magnetic information storage and memory technologies. I will discuss recent experiments on the optical manipulation of the magnetization of engineered materials and devices using 50-5000 fs optical pulses. We demonstrate that all optical switching can be observed in a broad range of materials and not...

QM simulations to identify improved photovoltaic materials

  • By Jenny Stein
  • 15 January 2020

Noa Marom leads a Carnegie Mellon University team in an Argonne Early Science Project with plans to use Aurora, Argonne's exascale supercomputer, to find materials that can increase the efficiency of solar cells. They use machine learning tools extensively in their research and are working with the developers of BerkeleyGW, SISSO, and Dragonfly software to prepare to run on the Aurora system.

According to Marom, “The goal of our research is to find new materials that make photovoltaic solar cells more efficient. The quest for any new materials that can enable new technologies is challenging. The materials we are researching have unique properties that make them suitable for use in solar cells, and these properties are very rare and difficult to find out of the wide array of possible materials. We are trying to accelerate the process of material discovery through computer simulation on high-performance computers (HPC) using sophisticated quantum-mechanical simulation software and machine learning (ML) tools. We are excited that our project has been accepted as one of the projects that will run on the future Aurora supercomputer as part of the Argonne ESP program. Our multi-institution team is currently modifying algorithms and workflows so they will be able to run on Aurora.”

Conference for Undergraduate Women in Physics

Multiple Speakers
Friday, January 17, 2020 - 12:00pm to Sunday, January 19, 2020 - 3:00pm

APS Conferences for Undergraduate Women in Physics (CUWiP) are three-day regional conferences for undergraduate physics majors held simultaneously around the US and Canada. Their goal is to empower undergraduate women and gender minorities in their pursuits and aspirations in the field of physics by providing them with an opportunity to connect with peers and leaders, learn strategies for success, and be inspired by experts.

The 2020 program in Pittsburgh will include research talks, panel discussions...

POSTPONED: Femto-magnetism meets spintronics: Towards integrated magneto-photonics

Bert Koopmans
Monday, March 30, 2020 - 4:00pm

Novel schemes for optically controlling ferromagnetic order at a femtosecond time scale receive great scientific interest. In the strongly non-equilibrium regime, it has become possible not only to quench magnetic order, but even to deterministically switch the magnetic state by a single femtosecond laser pulses. Moreover, it has been shown that pulsed laser excitation can induce spin currents over several to tens of nanometers. This development triggered a merge of the fields of ‘femto-magnetism’ and spintronics – opening up a fascinating playground for novel physical phenomena. In this...

'Dirty' Quantum Magnets

Itamar Kimchi
Thursday, January 30, 2020 - 3:30pm

Dr. Itamar Kimchi is currently an NRC postdoctoral fellow at JILA, the joint institute of NIST and the Department of Physics at the University of Colorado Boulder

Abstract: Studying quantum entanglement over the past decade has allowed us to make remarkable theoretical progress in understanding correlated many-body quantum systems. However in real materials electrons experience spatially random heterogeneities ("dirt") whose theoretical treatment, including strong correlations, has been a challenge. I will describe how synthesizing ideas from quantum information theory, statistical...

Guiding Principles for Engineering Quantum Matter far from Equilibrium

Martin Claassen
Thursday, January 23, 2020 - 3:30pm

One of the most fascinating aspects of non-equilibrium physics is that a macroscopic quantum system pushed out of equilibrium can exhibit markedly different dynamics when probed on different time scales. Pioneered in time-resolved condensed matter experiments and ultracold atoms, the idea to use external driving such as strong optical pulses holds promise to exceed the limitations set by chemistry and push materials into non-equilibrium states with novel or useful properties. However, a characterization of thermalization, order and dynamics far from equilibrium remains a fundamental...