Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session AA05: V: Undergrad Research IUndergrad Friendly
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Sponsoring Units: APS SPS Chair: Kayla Stephens, AIP Room: Virtual Room 5 |
Monday, March 20, 2023 5:00AM - 5:12AM |
AA05.00001: Tuning the Magnetic Phases of Iron Oxide Nanocubes Elizabeth A Chouinard The magnetic properties and biocompatibility of iron oxide nanoparticles allow for many uses in biomedical settings and other applications. Studies also indicate that iron oxide nanostructures could be used to enhance magnetic memory storage devices. This project aims to tune the different phases of iron oxide in order to optimize the magnetic properties. In the experiment, 30 nm iron oxide nanocubes were synthesized using a thermal decomposition process. After synthesis, the nanocubes were annealed at temperatures ranging from 150-300°C and for times ranging from 2-8 hours in order to optimize the iron oxide volume fractions. The 300 K magnetometry measurements showed that the coercivity increased after annealing whereas the 10 K magnetometry measurements displayed the opposite trend. However, the 10 K measurements showed an overall increase in coercivity due to the decrease in thermal energy as predicted by Bloch’s relation. Overall, these results not only indicate the kind of the magnetic behavior of the nanocubes (i.e., ferrimagnetic, superparamagnetic, etc.) but also help describe the crystallinity of the nanocubes since the crystallinity tends to increase with coercivity. Extensions of this project include using an inert gas while annealing to control the oxidation. |
Monday, March 20, 2023 5:12AM - 5:24AM |
AA05.00002: Phase Exploration in a SU(N)-Symmetric Singlet-Projector Model on the Diamond Lattice Using Quantum Monte Carlo. Artyom Filippov We search for exotic quantum phases, such as a spin-liquid phase, and phase transitions that break the traditional Landau-Ginzburg-Wilson (LGW) paradigm, i.e., deconfined quantum criticality, on a simple, local quantum magnetic model; specifically, the SU(N)-symmetric singlet-projector model, which exhibits magnetic order for small N. This model has no sign problem and is therefore easily studied using an exact quantum Monte Carlo algorithm known as the stochastic series expansion. Previous studies have already explored 2D square, honeycomb, triangular, kagome, and 3D pyrochlore lattices; the objective of this project is to consider the 3D diamond lattice to expand our search for exotic behavior. We intend to present evidence of the critical value of N beyond which magnetic order breaks down and then, with the help of additional interaction terms that allow us to tune to the transition point, a determination of the nature of the transition: first-order or continuous. This research was supported by the SURE (Summer Undergraduate Research Experience) award granted by the College of Natural Sciences & Mathematics at Sacramento State and an allocation of supercomputing time through XSEDE (DMR130040) on the Expanse cluster at the San Diego Supercomputing Center. |
Monday, March 20, 2023 5:24AM - 5:36AM |
AA05.00003: Utilizing an Adaptive Earth Mover's Distance to Detect Quantum Chaos Jessica K Jiang, Gary N Felder The correspondence between classical chaos and quantum mechanics is not well understood and is an active area of research. One understudied definition of quantum chaos directly borrows from that of its classical counterpart– a quantum system that is characterized by a positive Lyapunov exponent describing the exponential rate of separation of trajectories with infinitesimally close initial conditions in phase space. Describing an exponential rate of separation of trajectories is a challenging problem in quantum mechanics, as quantum systems are described by their Wigner function rather than a single point in phase space. One metric commonly used to define distances between probability density distributions is the Earth Mover's Distance, a distance that can be reformulated as a transportation problem. In this presentation, we show calculations of the Earth Mover's Distance over time of prototypical quantum states. Additionally, we present an adaptive Earth Mover's Distance method to compute distances between Wigner functions as a method of detecting quantum chaos. |
Monday, March 20, 2023 5:36AM - 5:48AM |
AA05.00004: Deposition of Pt/Co/Ir multilayer films with interfacial Dzyaloshinskii-Moriya interactions Yuqi Zhang, Andy T Clark, Mitchell Swyt, Kristen S Buchanan, Xuemei Cheng Multilayered thin films with interfacial Dzyaloshinskii-Moriya interactions (iDMI) can enable the formation of stable magnetic skyrmions at room temperature, which have potential for storage, logic, and neuromorphic computing applications [1-5]. Understanding of iDMI is key to designing optimized multilayer structure for device applications. Here we report deposition of Pt/Co/Ir multilayer films with perpendicular magnetic anisotropy (PMA) for investigating iDMI by Brillouin light scattering (BLS). We deposited Pt(1.5nm)/Co(1.0nm)/Ir(1.0nm) trilayer thin films with a Ta buffer layer and SiO2 capping layer on thermally oxidized Si wafer by DC magnetron sputtering with deposition rates for each layer previously calibrated by small angle x-ray reflectivity. Comparison of magnetic hysteresis loops obtained with in-plane and out-of-plane magnetic fields confirmed PMA in the deposited Pt/Co/Ir multilayer films. We have used BLS to quantify the iDMI in the deposited Pt/Co/Ir multilayers through measurement of the frequencies of counterpropagating surface spin waves as a function of the wavevector, and we find that the additional Ir layer leads to measurable changes in the iDMI as compared to [Pt/Co] bilayers. |
Monday, March 20, 2023 5:48AM - 6:00AM |
AA05.00005: Design of globally aligned multi-walled carbon nanotube (MWCNT) film reflector to enhance antenna directivity Angéline Lafleur, HeeBong Yang, Na Young Kim Carbon nanotubes are one-dimensional tube-shaped hexagonal lattice structures with a nanometer scale radius, that exhibit promising electrical, optical, and mechanical properties useful in nanotechnology. Specifically, multi-walled carbon nanotubes (MWCNT) made of concentric cylindrical carbon layers are shown to have higher conductivity, and are often dispersed in. Using a controlled slow vacuum filtration (SVF) process, globally aligned MWCNT films can be created from these solutions, and the fabricated films exhibit anisotropic conductivity which could be essential for creating ultra-light-weight reflector antennas. These high directivity antennas are often made with spaced metal strips to decrease weight while maintaining performance from the high conductivity in one specific axis. In this presentation, we examine the use of MWNCT films prepared using an automated SVF setup as reflectors to enhance the directivity of a 10 GHz dipole antenna. We compare the radiation efficiency and the radiation pattern of this antenna made of aligned MWCNT reflectors with standard metal reflectors. |
Monday, March 20, 2023 6:00AM - 6:12AM |
AA05.00006: A versatile shutter driver with integrated arbitrary waveform generator using a programmable system-on-chip (PSoC) device Justin M Craven, Gabe Delich, Elliott Meeks, Hyewon K Pechkis, Joseph A Pechkis We have developed a versatile mechanical shutter driver with integrated arbitrary waveform generator using a programmable system-on-chip (PSoC) device. This microcontroller-based device with configurable digital and analog blocks is readily reprogrammed using free software, allowing for easy customization for a variety of applications. Additional digital and analog outputs with arbitrary timings can be used to control a variety of devices, such as acousto-optical modulators, additional shutters, or camera trigger pulses, for complete control of optical switching and imaging of laser light. Utilizing TTL-level control signals, this device can be readily integrated into existing computer control and data acquisition systems for expanded hardware capabilities. We report on the performance of this device and its integration into cold atom experiments. |
Monday, March 20, 2023 6:12AM - 6:24AM |
AA05.00007: Active roles of Poynting vectors & π-phase shift in observing the superposition outputs through a Mach-Zehnder interferometer Chandrasekhar Roychoudhuri A Mach-Zehnder Interferometer (MZI) can generate fringes in two different modes. In the spatial fringe mode, two beams are aligned on the final beam combiner (BC), as spatially coincident, but with the beam-Poynting vectors set at a small angle. A CCD camera on either one of the output beams will execute the square modulus of the sum of the two complex amplitudes & generate the spatial cosine fringes. This is intrinsically a quantum process. The BC behaves as a fixed beam splitter. In the scanning-fringe mode, the two Poynting vectors for the two output beam-pairs, are made collinear. The fringes are displayed in the time domain on a dual-beam scope by opto-mechanically scanning one of the two MZI mirrors. The scanning sine & cosine fringes demonstrate the continuous re-direction of intensities from one port to the other port, underscoring the conservation of the total intensity. The classical transmitting and reflecting parameters of the BC execute the generation of the time-varying beam intensity re-direction depending upon the relative amplitudes and the two phases – the variable scanned phase and the fixed π-phase by the external boundary reflection of the BC. The educational lesson is this: In the scanning mode, the superposition energy re-direction is engendered by the classical boundary layer of the BC, not by any quantum phenomenon. Within the same generic superposition phenomenon, different physical light-matter interaction processes generate different kinds of cosine fringes. |
Monday, March 20, 2023 6:24AM - 6:36AM |
AA05.00008: Analyzing cholesteric liquid crystals' properties and their disordered helical textures Octavia D Ailsworth, Vianney K Gimenez-Pinto We investigate cholesteric liquid crystals and their helical textures using computational visualization tools and a finite-difference method for the director dynamics. We aim to understand what factors drive the disordered “focal conic” texture over the formation of a perfect planar helical texture. We review the properties of common liquid crystals compounds to incorporate in the simulation. Then, we analyze and systematically compare the texture formation and evolution for two different chiral nematic liquid crystals. |
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