Bulletin of the American Physical Society
Spring 2021 Meeting of the APS Ohio-Region Section
Volume 66, Number 3
Friday–Saturday, April 9–10, 2021; Virtual Meeting Hosted by John Carroll University, Cleveland Heights, OH; Time Zone: Eastern Daylight Time, USA
Session B01: Contributed Talks I |
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Chair: Niklas Manz, College of Wooster |
Saturday, April 10, 2021 8:00AM - 8:12AM |
B01.00001: Measuring Resistivity Change on Au (1,1,1) Thin Films and Installing an Argon Sputtering Device Ryan McGuinness, Dennis Kuhl We test the free electrons with random point scattering (FERPS) model by introducing dimethyl sulfide and dibutyl sulfide onto a gold (1,1,1) thin film in ultra-high vacuum and measuring resistivity both before and after dosing. Argon ion sputtering is used to ensure that the gold sample is clean prior to dosing. A temperature programmed desorption technique was used to look for adsorbates on the gold surface after dosing the sample. The FERPS model predicts an increase in resistivity. We have not detected an increase in resistivity of the thin film, but may have detected a decrease in resistivity when introducing dimethyl sulfide. [Preview Abstract] |
Saturday, April 10, 2021 8:12AM - 8:24AM |
B01.00002: Soluble Model of Interacting Spin-polarized Fermions in One Dimension Noah Kamm, Seth Grable, Harsh Mathur Quantum matter exists in a variety of remarkable states beyond the familiar categories of solid, liquid and gas. The state of a quantum many-body system is determined by the interactions amongst the particles. Problems of many interacting quantum particles are notoriously difficult to solve, but for particles in one dimension with a contact interaction, some exact results are known. Notably, for bosonic particles in one dimension with a delta function interaction, Lieb and Liniger found analytic solutions for various interaction strengths. These different states of one dimensional bosons have been studied experimentally by Kinoshita et al. in cold atom traps of Cesium atoms. However, for spin polarized fermionic particles with a delta function interaction it is known that they behave like a non-interacting fermion gas, regardless of the strength of the delta function potential. We have revisited this situation with a more general form of contact interaction recently discovered by Thompson et al. We predict that, under these interactions, the fermions form a new liquid state of fermionic matter that is reminiscent of Lieb-Liniger bosons. This novel state could be studied experimentally in cold atom traps loaded with suitable spin polarized fermions. [Preview Abstract] |
Saturday, April 10, 2021 8:24AM - 8:36AM |
B01.00003: Adjusting Images of a Conical Bead Pile through Linear Transformations Melita Wiles, Susan Lehman A conical bead pile is a used to model a system to learn about the behavior of granular systems. The pile is a critical system of roughly 20,000 steel beads atop a circular base; each bead is 3~mm in diameter. The pile is driven by adding one bead at a time to the pile apex. Any bead drop could trigger an avalanche, which we define as any number of beads leaving the pile. In order to analyze the dynamic behavior of individual avalanches, an aerial view camera records each avalanche at least 50 beads in size. We feed these images into a MATLAB program that analyzes the movement or velocity of sections of the pile. Since the camera cannot be directly above the apex of the pile, but is somewhat offset, the images produced are slightly distorted, leading to relative shifts in the velocity data for different locations on the pile. We reprocess the images taken by the camera using linear transformations through a homography matrix. This process is applied to batches of distorted images through a Mathematica program that produces the ideal viewpoint images. The technique will allow us to accurately analyze the pile behavior and movement of the beads on the pile, regardless of where the beads are located. [Preview Abstract] |
Saturday, April 10, 2021 8:36AM - 8:48AM |
B01.00004: True (though not in the cinematic sense) Grit Donald Priour Many porous materials, far from having well defined channels, instead consist of grains with random orientations, shapes, and sizes. For our purposes here, the latter two structural disorder elements, when present to a significant degree, characterize assemblies of grains henceforth referred to as "grit", where the range of volumes of irregularly shaped angular fragments may span several orders of magnitude. Whereas comparatively loose configurations of impermeable inclusions would allow fluid to flow, at high enough grain densities, void spaces no longer overlap to form a system spanning network, barring fluid transport on macroscopic scales. The shift with varying density among the former and latter scenarios is known as a percolation transition. With large-scale Monte Carlo simulations involving dynamical infiltration of tracer particles, we calculate the critical concentration for irregular grains generated by a stochastic fragmentation process in which randomly placed and oriented planes truncate initially cube shaped grains; as the slices accumulate, the distribution of shapes rapidly saturateds, even as the range of grain volumes continues to spread. Nevertheless, the critical porosity converges to just over 5% inspire of the steadily increasing grain mass variance. [Preview Abstract] |
Saturday, April 10, 2021 8:48AM - 9:00AM |
B01.00005: Nanoparticle Functionalization of Commercial Filtration Membranes for Water Purification Sean McBride This work highlights how monolayer thick, self-assembled nanoparticle membranes, made from 5 nanometer diameter gold nanoparticles encapsulated with an organic thiol molecule, can be transferred to commercially available filtration membranes to enhance the rejection of charged molecular dyes from water to nearly 100 percent rejection at a concentration of 145 micromolar. Molecular dyes are a serious contributor to waste water pollution in the textile industry. Most molecular dyes are made up of a negatively charged dye molecule and positive sodium ions that dissociate in aqueous solution, allowing for easy rejection measurements of both species. The negative dye molecule concentration in the feed and permeate can be measured using ultraviolet-visible spectroscopy, while the positive ions can be measured via ion specific conductivity measurements. Rejection measurements for the negative dye molecules will be presented for molecular dyes that vary systematically in ionic charge. With only 2.5 percent of all water on Earth being fresh water and with only 0.3 percent being accessible on the surface of the Earth, having access to fresh water is not only a problem of national significance, but one of global significance. [Preview Abstract] |
Saturday, April 10, 2021 9:00AM - 9:12AM |
B01.00006: Copper Iodide (CuI) Nanoparticles as a Hole Transport Layer to Cadmium Telluride (CdTe) Solar Cells. Dipendra Pokhrel, Ebin Bastola, Kamala Khanal Subedi, Suman Rijal, Manoj K Jamarkattel, Rasha Abbas Awni, Adam B Phillips, Yanfa Yan, Michael J Heben, Randy J Ellingson We report on the use of copper iodide (CuI) nanoparticles as a hole transport layer (HTL) on cadmium telluride (CdTe) solar cells. We synthesized the CuI NPs using solution precursors at room temperature. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to understand the morphological and structural properties of CuI NPs. The XRD pattern suggests pure $\gamma $-CuI phase in zinc-blend structure. The UV-vis absorption spectra of CuI NPs in dimethylformamide (DMF) solvent reveals a wide optical band gap energy of \textasciitilde 3.0 eV. Utilizing these CuI NPs as an interface layer, a photoconversion efficiency of 14.8 {\%} was measured with fill factor of 79.2 {\%} along with Au back electrode. The CuI NPs on CdS/CdTe device with indium tin oxide (ITO) as a back electrode enhances device performance as compared to cells without CuI NPs. The stability of the devices under thermal stress will be reported. [Preview Abstract] |
Saturday, April 10, 2021 9:12AM - 9:24AM |
B01.00007: Performance Evaluation of CuGaO$_{\mathrm{x}}$ Back Buffer Layer in Bifacial CdTe Solar Cells Aesha P. Patel, Kamala Khanal Subedi, Dipendra Pokhrel, Ebin Bastola, Adam B. Phillips, Michael J. Heben, Randy J. Ellingson Since thin-film CdTe device efficiency has reached 22.1{\%}, the next step is to use novel bifacial device configuration to increase energy yield per unit area. Polycrystalline CdTe is affected by interface defects at contacts, and back-contact challenges reduce device performance for back side illumination. Introducing a suitable back buffer layer can yield a positive initial Fermi level offset with the absorber layer. However, deep work function of CdTe (5.7 eV) limits development of a back buffer which can reduce interface defects and improve minority carrier lifetime and device performance for glass and film side illumination. Here, we used spin-coating to synthesize Cu$_{\mathrm{0.3}}$Ga$_{\mathrm{0.7}}$O$_{\mathrm{x}}$, a p-type transparent conductor serving as back-buffer layer for a CdTe cell. For bifacial architecture, these cells were completed with Sn-doped In$_{\mathrm{2}}$O$_{\mathrm{3}}$ (ITO) standard back contact. Time-resolved photoluminescence(TRPL), and current-voltage(J-V) measurements were recorded, and results of thermal stability testing will be reported. Our results showed improved carrier lifetime and device efficiency for cells with Cu$_{\mathrm{0.3}}$Ga$_{\mathrm{0.7}}$O$_{\mathrm{x}}$ back buffer for glass and film side illumination. [Preview Abstract] |
Saturday, April 10, 2021 9:24AM - 9:36AM |
B01.00008: Energy relaxation in a low-density nonequilibrium 2D hole gas at the quantum hall plateau-plateau transition Dimitrii Kruglov, Elina Klysheva, Andrei Kogan, Chieh-Wen Liu, Xuan Gao, Loren Pfeiffer, Kenneth West We have measured the derivative S = Rxy/dB of the transverse resistance Rxy vs magnetic field B at the 𝜈 =3 -> 𝜈 = 2 (B=0.45 T) quantum Hall plateau-plateau transition (PPT) , as function of the sample temperature T and dissipated Joule’s power P in a low-density, p-doped GaAs/AlGaAs quantum well with a high interaction parameter rs ~ 23 (nh= 2.9 x 1010 /cm-2 , hole mobility µ = 2.4 x 105 cm2/Vs). We present P-T curves constructed by matching P and T values at a given S, and compare these to a set of similar curves obtained for the sample resistance R at B=0. At low temperatures, the P-T data in the magnetic field and at B=0 diverge, suggesting that the thermal coupling between the holes and the lattice increases in the magnetic field and makes the holes effectively cooler at a given P. We also find that the thermal coupling in the magnetic field shows a weaker temperature dependence than at B=0. We compare these findings to an earlier work on a system with a lower rs=2.17 [1] and compere to available theoretical predictions. [1] Edmond Chow, H. P. Wei, S. M. Girvin, and M. Shayegan, Physical review letters, 1996. Vol. 77(6), pp 1143-1146. [Preview Abstract] |
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