Seminars

Abstract: The breaking of time-reversal symmetry in topological insulators leads to novel quantum states of matter. One prominent example at the two-dimensional limit is the Chern insulator, which hosts dissipationless chiral edge states at sample boundaries. These chiral edge modes are perfect one-dimensional conductors whose chirality is defined by the material magnetization and in which backscattering is topologically forbidden. Recently, van der Waals topological magnet MnBi2Te4 emerged as a new solid-state platform for studies of the interplay between magnetism and topology. I will present an overview of our progress toward controlling topological phase transitions and chiral edge modes in MnBi2Te4. First, I will establish how topological properties are intimately intertwined with magnetic states. I will then demonstrate electrical control of the number of chiral edge states and the discovery of chiral edge modes along crystalline steps between regions of different thicknesses and how these modes can be harnessed for the engineering of simple topological circuits. Finally, I will discuss the engineering of the superconducting state in topological insulators and demonstrate Pauli paramagnetic limit violation in atomically thin flakes of a topological superconductor candidate.

DiffDock: Diffusion Steps, Twists, and Turns for Molecular Docking

Passcode: SUn$qNe2

Abstract: Molecular docking, the process of predicting how small molecule ligands bind to proteins, is pivotal in drug design. Our work introduces a novel perspective by conceptualizing molecular docking as a generative modeling challenge. We present DiffDock, a diffusion generative model that operates on the complex, non-Euclidean manifold of ligand poses, efficiently navigating through the translational, rotational, and torsional degrees of freedom essential for accurate docking. Our empirical results showcase DiffDock's superiority, achieving a 38% top-1 success rate (RMSD<2Å) on the PDBBind dataset, markedly surpassing both traditional (23%) and other deep learning methodologies (20%). Notably, DiffDock demonstrates remarkable performance on computationally folded structures, achieving more than double the accuracy of existing methods. This talk will delve into the intuition and methodology behind DiffDock, and its strengths and limitations.

Abstract: In this talk I will discuss open questions in our quest to develop a map between progenitor systems and supernova explosions. Solving the puzzle has important ramifications for understanding the chemical enrichment of the Universe and galactic evolution and feedback. I will highlight Type Ia supernovae and discuss an exquisite set of observations obtained by the Zwicky Transient Facility (ZTF). From the early observations we can constrain the progenitors, and we have recently identified a new subclass of peculiar Type Ia supernovae that comes from a unique progenitor channel. To close I will discuss a new project, the La Silla Schmidt Southern Survey (LS4). LS4 will complement observations from the upcoming Rubin Observatory Legacy Survey of Space and Time (LSST) by providing observations of bright and fast transients that will be missed by LSST.

Abstract: We are interested in growing new inorganic materials in thin film form and tuning their physical properties through size, chemical doping, interface, and external tuning parameters (light, magnetic field, etc.). In the past few years, my group has focused on the growth and investigation of magnetic thin films for application in emerging nanotechnology areas such as spintronics. This effort has involved several graduate and undergraduate students and led to 2 Master's and 2 PhD’s in the past three and half years. For this talk, after a brief overview of the research area and the desired functional properties, I will present the results of a theory-driven experimental search of novel magnetic materials that potentially support the desired properties. Thermodynamically stable binary and ternary materials were identified in prior theoretical searches in the Heusler family (general formula X2YZ). Among them, we are interested in Mn-based ternary alloys due to their tunable magnetic and crystal properties. Using the magnetron co-sputtering method, we synthesized potentially high-performance Mn3-xFexSn thin films with x= 0, 1, and 2 and evaluated the structural, magnetic, and electrical properties. All samples grew polycrystalline with a hexagonal phase. Electric transport measurements revealed a non-metallic behavior for Mn2FeSn, whereas Fe2MnSn and Mn3Sn showed metallic behavior. Mn3Sn exhibited a low magnetic moment (0.4 μB/f.u). The addition of Fe increased the moment to 3.5 μB/f.u (Mn2FeSn) and 4.7 μB/f.u (Fe2MnSn). Mn2FeSn displayed a large exchange bias effect with the coexistence of antiferromagnetic and ferromagnetic phases below room temperature, whereas Fe2MnSn demonstrated a robust ferromagnetic phase with a Curie temperature of 512 K. Both materials exhibited a sizable magnetic anisotropy of close to 0.5 MJ/m3 at 2 K. Still, only Fe2MnSn is viable for spintronics applications due to its room-temperature functionality.

Applications of Quantum Computing for Problems in Chemistry and Material Sciences

Passcode: y@6=b@6E

Abstract: The field of quantum computing has made a lot of progress in the past decade with respect to new algorithms and hardware. Tied in with this progress comes an important question, how to get utility from the current generation of quantum hardware and algorithms. In this talk, a few examples of applications of quantum computing in the field of chemistry and material sciences will be discussed. This will provide an overview of different algorithms and techniques used for obtaining results from the current generation of quantum hardware. In addition, an outlook for the applications of quantum computers for chemical and material use cases will be presented.

Note: Dr. Guo will also give a Chemistry & Biochemistry seminar on Wednesday, April 10, titled "Chemistry and Thermodynamics of f-block Condensed Materials: From Nuclear Fuels to Waste Forms

Abstract: Critical metals, including rare earth elements (REE), U and Th, are in high demand due to their pervasive use in emerging technology and renewable energy applications. Understanding their thermodynamic parameters is crucial for predicting their transport, deposit, and alteration behaviors in relevant geological conditions (e.g., extreme conditions). In our group, we use a set of structural-thermodynamic techniques to in situ probe chemical and physical changes of critical metal materials under elevated pressure and/or temperature conditions. Specifically, high temperature calorimetry and in situ high temperature X-ray diffraction (XRD) were implemented to investigate phase transition and corresponding enthalpies of reaction and mixing. The high pressure structures and equation of states were studied by coupled diamond anvil cell with synchrotron for in situ high pressure XRD, along with density functional theory (DFT). The elastic constants can also be obtained by resonant ultrasonic spectroscopy. By combining these methods, we can obtain more comprehensive thermodynamic parameters for relevant REE mineral phases. In this talk, I will discuss our recent finding on the high pressure structures of zircon, xenotime-type minerals (commonly accommondating REE and actinides), high temperature transitions of REE phosphates, and thermodynamic of mixing of REE phosphate and carbonate mineral phases.

Zoom seminar ID: 915 2072 1543

Abstract: Incorporating molecular nanolayers (MNLs) at inorganic interfaces offers promise for reaping unusual enhancements in fracture energy, and thermal and electrical transport. In this talk, I will discuss how multilayering MNL-bonded inorganic interfaces results in viscoelastic damping bandgaps. Molecular dynamics simulations of Au/octanedithiol MNL/Au multilayers reveal high-damping-loss frequency bands at 33 ≤ ν ≤ 77 GHz and 278 ≤ ν ≤ 833 GHz separated by a low-loss bandgap 77 ≤ ν ≤ 278 GHz region. The viscoelastic bandgap scales with the Au/MNL interface bonding strength and density, and MNL coverage. These results and the analyses of interfacial vibrations indicate that the viscoelastic bandgap is an interface effect that cannot be explained by weighted averages of bulk responses. Subsequently, I will delve into the tunability of thermal conductivity of Au/MNL nanolaminates via. interfacial bonding by (i) homogeneous change of bonding strength and heterogeneous change of (ii) bond density and (iii) molecular coverage at the interfaces. By comparing the thermal conductivity of the nanolaminates with the interfacial thermal conductance of corresponding individual interfaces, we showed that phenomenologically the thermal conductivity can be predicted from independent interfacial resistors connected in a series model, particularly at higher temperatures. Furthermore, I will discuss the utilization of phonon wave packet simulations at individual and multiple interface structures to shed light onto the observations from direct MD simulations.

Zoom seminar ID: 915 2072 1543

Abstract: This talk aims to correct some common misconceptions you might have about teaching. It will go over some advantages and disadvantages of teaching, including the perspective from teaching at a community college rather than a four year university or high school, with comments from the perspective of someone who teaches at a community college and has briefly taught for high school.

Hydration Solids

What I thought I learned, what I actually learned, and what I wished I learned from getting a bachelors in Physics

(i) Fully funded Ph.D. opportunities in MSEC at Texas State University
(ii) UWBG Carbon for Electronic Applications

Emerging Nanomaterials & Composites for Electronics, Energy & Environmental Applications

Accelerated Variational Quantum Eigensolver with Joint Bell Measurement
Zoom Passcode: VSc0M.pj

Inversion and Time-reversal Symmetry Broken Weyl Semimetal
Zoom Passcode: 23tqmd!Y

Calculating Vibrationally Averaged Molecular Properties with Multicomponent Methods

Epitaxial AlScN Films and Nanowires for Ferroelectric Random-Access Memory Applications

Dr. Elisabeth Mills
University of Kansas

Simon Batzner
Harvard University

Fundamentals of Amorphous Oxide Semiconductors

Phase-field Modeling of Ferroelectrics: Polarization Rotation and Flexoelectricity

Materials Discovery through Machine Learning: Experimental Validation and Interpretable Models

High-throughput Investigations of Phase Formation and Mechanical Properties in Complex Metallic Alloys

2010 Alumni Update: Career Paths, Thermal Management R&D, and In-state Job Opportunities

Experimental Particle Physics and Tracking Detectors

Christian Stepien (PAMS)

3/24

Predicting Multiscale Responses of Organic High Explosives Subjected to Thermo-Mechanical Extremes

Rifat Ara Shams (PAMS)

Dr. Yicheng Guo
University of Missouri - Columbia

Dissecting Distant Galaxies: How Sub-structures Shed Light on Galaxy Formation and Evolution

Dr. Maria Mills
University of Missouri - Columbia

Modeling Atomic Layer Deposition of Alumina as an Ultra-thin Tunnel Barrier using Reactive Molecular Dynamics

Dr. Jason Jackiewicz
New Mexico State University

Alin Niraula (PAMS)

Dr. Paul Canfield
Ames National Laboratory &
Iowa State University

A Study of Laser-assisted Chemical Vapor Deposition (CVD) Technique to Grow Carbon-based Materials

Yuxuan Lu (PAMS)

Rajan Khadka (PAMS)

Hayley Sohn (PhD student, alum)
University of Colorado Boulder

Active Liquid Crystal Skyrmions

10/16

Dr. Lloyd Lumata
University of Texas Dallas

Hyperpolarized Magnetic Resonance: Enhancing NMR and MRI Signals by >10,000-fold for Real-Time Metabolic Assessment of Cancer

Dr. Marco Cavaglià
Missouri University of Science and Technology

Promising Candidates for Topological Superconductors