Condensed Matter Physics Commons^™

Analysis Of Electron Yield Properties Of Low-Density Polyethylene, Jr Dennison, Jordan Lee

Posters

At extremely high altitudes, spacecraft are submitted to solar radiation of varying charged-particle fluxes. This radiation can induce charging of the spacecraft itself, creating unwanted and disastrous effects on electrical components from electrostatic breakdown or arc-induced damage of structural or optical components. To prevent these effects, space-like environment tests are performed on materials to understand how they interact with the space plasma environment.

Radiation Damage Threshold Of Satellite Cots Components: Raspberry Pi Zero For Opal Cubesat, Jonh Mojica Decena, Brian Wood, Ryan J. Martineau, Jr Dennison, Michael Tayor

Posters

The use of inexpensive microprocessors or commercial of the shelf (COTS) components is one of the most common cost-saving methods in the constructions of CubeSats. Design of electronics that can maintain full functionality over the duration of the mission requires careful determination of the space radiation environment and total ionizing dose (TID) delivered to the components. Larger, more expensive or longer mission satellites tend to use more expensive components than the ones used in CubeSat to assure reliability. Radiation survivability of a Raspberry Pi Zero was studied with the USU Space Survivability Test Chamber using 0.2 to 2.5 MeV beta …

The Effects Of Beta Transition On Dielectric Breakdown In Ldpe, Tyler Kippen, Allen Andersen, Jr Dennison

Presentations

No abstract provided.

Effects Of Acoustic Coupling Layer Electrical Conducitivity On Pulsed Electroacoustic Measurements, Zachary Gibson, Jr Dennison, Lee Pearson, Erick Griffiths, Anthony Pearson

Posters

No abstract provided.

Radiation Damage Threshold Of Satellite Cots Components: Raspberry Pi Zero For Opal Cubesat, Jonh Mojica Decena, Brian Wood, Ryan J. Martineau, Michael Tayor, Jr Dennison

Posters

No abstract provided.

Analysis Of Electron Yield Properties Of Low-Density Polyethylene, Jordan Lee, Jr Dennison

Posters

No abstract provided.

Quasiprobability Behind The Out-Of-Time-Ordered Correlator, Nicole Yunger Halpern, Brian Swingle, Justin Dressel

Mathematics, Physics, and Computer Science Faculty Articles and Research

Two topics, evolving rapidly in separate fields, were combined recently: the out-of-time-ordered correlator (OTOC) signals quantum-information scrambling in many-body systems. The Kirkwood-Dirac (KD) quasiprobability represents operators in quantum optics. The OTOC was shown to equal a moment of a summed quasiprobability [Yunger Halpern, Phys. Rev. A 95, 012120 (2017)]. That quasiprobability, we argue, is an extension of the KD distribution. We explore the quasiprobability's structure from experimental, numerical, and theoretical perspectives. First, we simplify and analyze Yunger Halpern's weak-measurement and interference protocols for measuring the OTOC and its quasiprobability. We decrease, exponentially in system size, the number of trials …

Resonant Tunneling Across A Ferroelectric Domain Wall, M. Li, L. L. Tao, J. P. Velev, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Motivated by recent experimental observations, we explore electron transport properties of a ferroelectric tunnel junction (FTJ) with an embedded head-to-head ferroelectric domain wall, using first-principles density-functional theory calculations. We consider a FTJ with La_0.5Sr_0.5MnO₃ electrodes separated by a BaTiO₃ barrier layer and show that an in-plane charged domain wall in the ferroelectric BaTiO₃ can be induced by polar interfaces. The resulting V-shaped electrostatic potential profile across the BaTiO₃ layer creates a quantum well and leads to the formation of a two-dimensional electron gas, which stabilizes the domain wall. The confined electronic states …

Characterizing The Effects Of Radiation On Muscle Cells, Lori Caldwell, Charles Harding, Eryn Hanson, Jr Dennison, Elizabeth Vargis

Presentations

No abstract provided.

Coarse-Grained Modeling Studies Of Polymeric And Granular Systems, Hong Trung Nguyen

USF Tampa Graduate Theses and Dissertations

This Dissertation is devoted to computational study of the solidification, dynamics and mechanics of model semiflexible polymers with variable chain flexibility as well as a computational investigation of the clogging phenomena observed in granular materials.

Chain stiffness is an intrinsic factor that governs single-chain flexibility. It plays a critical role in the physics of polymeric materials. In this work, we employ a coarse-grained polymer model in which chain stiffness can be tuned by a single parameter (bending stiffness kb) that yields chain shape ranging from coil-like to rod-like in the flexible and very stiff limit respectively. In chapter 2, we …

Dielectric Properties Of Thin Cr2o3 Films Grown On Elemental And Oxide Metallic Substrates, Ather Mahmood, Mike Street, Will Echtenkamp, Chun Pui Kwan, Jonathan P. Bird, Christian Binek

Christian Binek Publications

In an attempt to optimize leakage characteristics of α-Cr₂O₃ thin films, its dielectric properties were investigated at local and macroscopic scale. The films were grown on Pd(111), Pt(111), and V₂O₃ (0001), supported on Al₂O₃ substrate. The local conductivity was measured by conductive atomic force microscopy mapping of Cr₂O₃ surfaces, which revealed the nature of defects that formed conducting paths with the bottom Pd or Pt layer. A strong correlation was found between these electrical defects and the grain boundaries revealed in the corresponding topographic scans. In comparison, …

Predicting The Ground-State Structure Of Sodium Boride, Xin-Ling He, Xiao Dong, Quansheng Wu, Zhisheng Zhao, Qiang Zhu, Artem R. Oganov, Yongjun Tian, Dongli Yu, Xiang-Feng Zhou, Hui-Tian Wang

Physics & Astronomy Faculty Research

Binary borides has been a subject of extensive research. However, the exact compositions and crystal structures of sodium borides remained controversial. Here, using the ab initio variable-composition evolutionary algorithm, a new stable Na2B30 with I212121 symmetry (I212121-Na2B30) is found, which is -7.38meV/atom lower in energy than the Imma-Na2B30 structure reported by experimentalists. Interestingly, the Imma-Na2B30 structure is predicted to be a topological nodal line semimetal, which may result in superior electronic transport. In contrast, I212121-Na2B30 is an ultrahard semiconductor with an unprecedented open-framework structure, whose interstitial helical boron sublattice enhances its hardness and energetic stability.

Functionalized Nanoporous Carbon Scaffolds For Hydrogen Storage Applications, Christopher Carr

Dissertations

Recent efforts have demonstrated confinement in porous scaffolds at the nanoscale can alter the hydrogen sorption properties of metal hydrides, though not to an extent feasible for use in onboard hydrogen storage applications, proposing the need for a method allowing further modifications. The work presented here explores how the functionalization of nanoporous carbon scaffold surfaces with heteroatoms can modify the hydrogen sorption properties of confined metal hydrides in relation to non-functionalized scaffolds (FS). Investigations of nanoconfined LiBH₄and NaAlH₄indicate functionalizing the carbon scaffold surface with nitrogen can shift the activation energy of hydrogen desorption in excess of …

Polarization-Controlled Modulation Doping Of A Ferroelectric From First Principles, Xiaohui Liu, Evgeny Y. Tsymbal, Karin M. Rabe

Evgeny Tsymbal Publications

In a ferroelectric field effect transistor (FeFET), it is generally assumed that the ferroelectric gate plays a purely electrostatic role. Recently it has been shown that in some cases, which could be called “active FeFETs,” electronic states in the ferroelectric contribute to the device conductance as the result of a modulation doping effect in which carriers are transferred from the channel into the ferroelectric layers near the interface. Here we report first-principles calculations and model analysis to elucidate the various aspects of this mechanism and to provide guidance in materials choices and interface termination for optimizing the on-off ratio, using …

Dissipation Effects In Schrödinger And Quantal Density Functional Theories Of Electrons In An Electromagnetic Field, Xiao-Yin Pan, Viraht Sahni

Publications and Research

Dissipative effects arise in an electronic system when it interacts with a time-dependent environment. Here, the Schrödinger theory of electrons in an electromagnetic field including dissipative effects is described from a new perspective. Dissipation is accounted for via the effective Hamiltonian approach in which the electron mass is time-dependent. The perspective is that of the individual electron: the corresponding equation of motion for the electron or time-dependent differential virial theorem—the ‘Quantal Newtonian’ second law—is derived. According to the law, each electron experiences an external field comprised of a binding electric field, the Lorentz field, and the electromagnetic field. In addition, …

Nv Center Detection Of Electric Fields And Low-Intensity Light, Nicholas Harmon, Michael Flatte

Faculty Works

Nitrogen vacancy (NV) center spins in diamond are attractive candidates for quantum information processing and sensitive, nanoscale magnetometers due to their long spin coherence times under ambient conditions [1]. The ground state of the NV spin is also sensitive to electric fields [2]. We present a theory of quantum detection using positive operator valued measurements (POVMs) wherein the presence of an electric field is determined by spin-dependent fluorescence of an NV center. The predicted sensitivity to small electric fields can also be used for photon detection. Photons incident upon a chromophore near the diamond interface may induce a charge polarization …

Effects Of Acoustic Coupling Layer Electrical Conductivity On Pulsed Electroacoustic Measurements, Zachary Gibson, Jr Dennison, Lee Pearson, Erick Griffiths, Anthony Pearson

Posters

The spatial resolution of Pulsed Electroacoustic (PEA) measurements can be limited by the acoustic thickness of the coupling material coupling the sample to the detector assembly. Our investigations studied the effect of adhesive material and thickness to optimize the quality of the PEA signal.

Nanostructural Origin Of Semiconductivity And Large Magnetoresistance In Epitaxial Nico2O4/Al2O3 Thin Films, Congmian Zhen, Xiaozhe Zhang, Wengang Wei, Wenzhe Guo, Ankit Pant, Xiaoshan Xu, Jian Shen, Li Ma, Denglu Hou

Xiaoshan Xu Papers

Despite low resistivity (~1 mΩ cm), metallic electrical transport has not been commonly observed in inverse spinel NiCo₂O₄, except in certain epitaxial thin films. Previous studies have stressed the effect of valence mixing and the degree of spinel inversion on the electrical conduction of NiCo₂O₄ films. In this work, we studied the effect of nanostructural disorder by comparing the NiCo₂O₄ epitaxial films grown on MgAl₂O₄ (1 1 1) and on Al₂O₃ (0 0 1) substrates. Although the optimal growth conditions are similar for the …

Coexistence Of Ferromagnetism And Unconventional Spin-Glass Freezing In The Site-Disordered Kagome Ferrite Srsn2Fe4O11, L. Shlyk, S. Strobel, Barry Farmer, Lance E. De Long, R. Niewa

Physics and Astronomy Faculty Publications

Single-crystal x-ray diffraction refinements indicate SrSn₂Fe₄O₁₁ crystallizes in the hexagonal R-type ferrite structure with noncentrosymmetric space group P6₃mc and lattice parameters a = 5.9541(2)Å, c = 13.5761(5)Å, Z = 2 (R(F) = 0.034). Octahedrally coordinated 2a [M(1) and M(1a)] and 6c sites [M(2)] have random, mixed occupation by Sn and Fe; whereas the tetrahedrally coordinated 2b sites [Fe(3) and Fe(3a)] are exclusively occupied by Fe, whose displacement from the ideal position with trigonal-bipyramidal coordination causes the loss of inversion symmetry. …

Electronic And Optical Properties Of La-Doped Sr3Ir2O7 Epitaxial Thin Films, Maryam Souri, Jsaminka Terzic, J. M. Johnson, John G. Connell, John H. Gruenewald, J. Thompson, Joseph W. Brill, J. Hwang, Gang Cao, Sung S. Ambrose Seo

Physics and Astronomy Faculty Publications

We have investigated structural, transport, and optical properties of tensile strained (Sr_1−xLa_x)₃Ir₂O₇ (x = 0, 0.025, 0.05) epitaxial thin films. While high-T_c superconductivity is predicted theoretically in the system, we have observed that all of the samples remain insulating with finite optical gap energies and Mott variable-range hopping characteristics in transport. Cross-sectional scanning transmission electron microscopy indicates that structural defects such as stacking faults appear in this system. The insulating behavior of the La-doped Sr₃Ir₂O₇ thin films is presumably due to disorder-induced …