Previous APMS Colloquia

Fall 2024

Thursday, October 10, 9:45-10:45 am

Designing Topological Semimetals for New Energy Arenas

Abstract: The growing use of computing in the age of Al is projected to place more demand on our energy infrastructure and will ultimately necessitate the use of more energy efficient microelectronics. Innovations in spintronic and neuromorphic devices will in turn require us to develop new materials that better enable the control of flow of electrons and their spin states. In this talk, I will discuss the potential of topological semimetals for microelectronics applications and the early-stage materials manipulation work that will need to be conducted in preparation for more advanced device development. We use the Dirac semimetal CdAs as a platform to study the role that typical forms of disorder, such as point defects, play in electron transport behavior. We also demonstrate paths toward device design utilizing topological semimetals and discuss what is next in this field.

Kirstin Alberi is the Director of the Materials Science Center in the Materials, Chemical and Computational Science directorate at the National Renewable Energy Laboratory (NREL). She received a doctorate in materials science and engineering from the University of California, Berkeley in 2008, where she studied the optical and electronic properties of highly mismatched semiconductor alloys. She came to NREL as a postdoctoral researcher in the Silicon Materials and Devices group to investigate the design and performance of thin crystalline silicon (c-Si) solar cells fabricated on inexpensive substrates. In 2010, Kirstin joined the Materials Physics group to conduct basic research on the optical and electronic properties of semiconductor alloys for photovoltaic, solid-state lighting and other energy-relevant technologies.

Thursday, September 26, 9:45-10:45 am

The nexus of nonproliferation, nuclear energy and safeguards projects – A scientist’s perspective

Abstract: This presentation provides a detailed review of several active projects at Idaho National Laboratory (INL) that stand at the intersection of nuclear
nonproliferation, nuclear energy, and safeguards. The importance of a comprehensive educational background in nuclear sciences is underscored, along with the necessity for
collaborative work within diverse multidisciplinary teams. The presentation illustrates how combining diverse expertise is crucial for the ongoing development of the nation’s
nuclear industry and paramount for addressing sophisticated, cutting-edge questions in the field of nuclear science and technology.

Dr. Luis Ocampo Giraldo is a scientist, team leader, and principal investigator in the nuclear nonproliferation division at Idaho National Laboratory. He has a decade of
experience related to gamma-ray spectrometry, development of methods, instruments, and systems for detecting and measuring radiation, data acquisition, hardware
interface, seismoacoustics, and signal processing. As a principal investigator, he oversees multiple research projects sponsored by DOE, NNSA and NE leading diverse
teams to address the application of nondestructive assay and nontraditional sensing techniques to tackle challenges within the nuclear regime. His research has advanced
semiconductor radiation detectors and arrays, improved radiation monitoring technologies, and contributed to the development of advanced nuclear fuels.

Thursday, September 5, 9:45-10:45 am

An Equitable and Just Energy Future

Spring 2024

Thursday, April 18, 3:00-4:00 pm

Membranes for Clean Energy and Sustainable Environment

Abstract: In the coming decade, membrane science will play an important role in addressing non thermal based separation needs for various clean energy technologies and helping the world to achieve a sustainable environment. Specific applications like, H₂ utilization and production, CO₂ capture and reuse, plastic deconstructions, chemical process separations and water purifications are noteworthy. On one hand each of these applications has specific performance metrices, on the other hand they share a common fundamental question; relation of membrane structure to transport of various species. In addition to understanding the structure-property relationships, membrane fabrication, and prototype testing are additional research areas for accelerating membrane development. These areas sit at the intersection of engineering, basic science, and science policy and partnerships. There is a need to develop a cross-functional, inter-agency membrane platform initiative to drive such goals. The presentation will focus on key membranes application areas like H₂ fuel cells, water purification, waste plastic circularity, and carbon capture, emphasizing recent developments, market and societal needs, and proposed research topics.

Thursday, April 4, 3:00-4:00 pm

Young Binary Stars and Planet Formation

Abstract: As a solitary star with no stellar companion, our Sun is in the minority: at least 60-70% of stars are located in systems of two or three or more components. For the study of star and exoplanet formation, binary stars represent both an opportunity and a problem. On one hand, simple Keplerian physics yields dynamical stellar mass, the most fundamental property of a star, as well as orbital characteristics. Binary star components’ shared age and environment also provides a useful control on comparisons of physical properties. On the other hand, location in a multiple star system impacts the evolution of planet-forming circumstellar disk material and complicates scientists’ identification of individual stellar properties. Nevertheless, given their ubitquity and usefulness, young binaries merit close attention. In the context of the relevant applied physics, e.g., mechanics, spectroscopy, and statistical mechanics, I will describe my research on the determination of young star masses and the potential for planet formation in the binary star environment. I will highlight the contributions of my team, including a number of NAU students, to these efforts.

Thursday, March 28, 3:00-4:00 pm

Can we make safe and affordable batteries for electric cars and large scale grid storage? A personal view through recent liquid state and solid state nuclear magnetic resonance investigations of novel electrolytes

Abstract: All major automobile companies will cease manufacturing internal combustion-powered vehicles within a timeframe measured in years rather than decades. The need for mitigating “range anxiety” affordably and without sacrificing safety presents a major challenge to present-day lithium ion technology, which has nearly reached its physical limit in energy density. New chemistries with correspondingly new materials are needed for the next generation of batteries. The major bottleneck in all of these current and proposed developments is the lack of a suitable electrolyte needed to eliminate the flammable liquid carbonate electrolyte solvents in use today. In the realm of large scale grid storage, redox flow batteries, in which energy is stored in large electrolyte-containing tanks, are leading candidates because they are not “footprint” limited.

Our laboratory is focused on application of various nuclear magnetic resonance (NMR) techniques to help understand structure and dynamics of energy storage materials, in particular novel electrolytes. In this presentation we discuss two recent collaborative efforts.

(i) Deep eutectic solvents (DES), are defined as a mixture of two or more species, typically a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA) which may be solid or liquid, and that at a particular composition present a melting point depression usually resulting in being a liquid at room temperature. Among their most relevant properties are low volatility, low flammability and wide electrochemical and thermal stability windows. Unlike typical ionic liquids, DESs can be inexpensive, readily synthesized, and can often be prepared from biodegradable, and nontoxic constituents. This makes them attractive candidates, when suitable electrochemically active reagents are added, for redox flow battery applications.¹ For the work described in this presentation, in collaboration with the University of Tennessee and Case Western University, the molecular rotational and translational dynamics of several different DESs based on choline chloride (ChCl) were studied using the fast field-cycling nuclear magnetic resonance relaxometry (FFC-NMR) and pulsed-field gradient (PFG) NMR techniques.¹

(ii) The second project (with L. Hu, et.al., University of Maryland) concerns cellulose nanofibers (CNF) derived from natural wood materials. Introducing Cu²⁺ into the CNF creates molecular channels through which Li⁺ ions can more readily move. Solid state magic angle spinning (MAS) ¹H NMR provides estimates of the residual solvent molecules present in Li-Cu-CNF materials, which aids the Li⁺ ions transport mechanism without compromising electrochemical stability. PFG NMR was used to measure the diffusivity of Li⁺ and anion and to estimate the Li⁺ transference number (t_Li+), which turns out to be significantly greater than observed in other polymer-based electrolytes.²

Finally, time permitting, aspects of my own personal views and experiences on student mentoring will be presented.

1. “Dynamics of Glyceline and Interactions of Constituents: A Multi-technique NMR study”, C. Fraenza, et.al. Journal of Physical Chemistry B, 126, 890 (2022) https://doi.org/10.1021/acs.jpcb.1c09227

2. “Copper-coordinated cellulose ion conductors for solid-state batteries”, Chunpeng Yang et al., Nature 598, pages, 590 (2021) https://doi.org/10.1038/s41586-021-03885-6

Thursday, February 22, 3:00-4:00 pm

Interfacial Reactions in Materials using Advanced Microscopy

Abstract: An interfacial understanding is needed in many material science challenges, where we have used advanced microscopy techniques for corrosion, Li-metal batteries, and degraded solar modules. The electrode-electrolyte interface is challenging to probe, but new methods and tools are enhancing our understanding of these interfaces. Liquids pose a significant challenge for high-resolution scanning transmission electron microscopy (STEM) due to the high vacuum environment required for optimal imaging conditions. Two strategies will be covered in this seminar, operando liquid-phase STEM and cryogenic STEM, for characterizing nanoscale detail from these solid-liquid interfaces. Our objective understanding of these nanoscale mechanisms can be greatly improved by combining the high-resolution detail with micro-to-millimeter scale compositional and structural mapping with cryogenic focused ion beam scanning electron microscopy. This seminar will cover the use of these advanced microscopy methods for low-carbon steel corrosion that identifies a possible mechanism for pit formation, morphology of electrodeposited lithium metal in aprotic solvents, and encapsulant reactions at a silicon solar cell surface from water and sodium migration. The tools, methods, and results of these studies will be detailed in this presentation.

Thursday, January 25, 3:00-4:00 pm

Integration of Physics and Engineering at Idaho National Laboratory

Abstract: Idaho National Laboratory is a Department of Energy site spreading over 890 square miles. With four operating nuclear reactors, it is the primary DOE facility for nuclear research, but has a recent expansion in cybersecurity and critical infrastructure. The integration of physics and engineering provides a better understanding for concepts found in these fields. For nuclear research, the concentration of radioactive isotopes is an important parameter to measure in operating reactors and predictions for potenital reactor designs. For isotopes that possess a complicated decay diagram, angular coincidences between gamma rays emitted in a single atomic decay can be measured with two radiation detectors and will lower the sensitivity of a detection system. The Germanium Rotational Measurements for Angular Correlation (GeRMAC) system has been assembled at INL to provide data for nuclear reactor, radiation detector, and nuclear forensics measurements.