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2013

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Articles 301 - 330 of 1248

Full-Text Articles in Physics

Optimization Of Carbon Nanotube Aggregation Process And Other Work For The Byu Nanotechnology Research Group, David Brown, Dr. Robert Davis Aug 2013

Optimization Of Carbon Nanotube Aggregation Process And Other Work For The Byu Nanotechnology Research Group, David Brown, Dr. Robert Davis

Journal of Undergraduate Research

In my two years of doing research at BYU, I’ve learned that the only true constant in the lab is change. Success in research seems to be determined not only by our hard work and preparation but also by our ability to be flexible and adapt our work to fit the conditions. With luck, the progress we do make will help work towards our overall goal, even if we have to use unexpected methods to get there. My research project this year was a perfect example of unexpected setbacks and insurmountable obstacles, but my lab experience in general has been …

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Asymmetric Architecture For Heralded Single-Photon Sources, Luca Mazzarella, Francesco Ticozzi, Alexander V. Sergienko, Giuseppe Vallone, Paolo Villoresi Aug 2013

Asymmetric Architecture For Heralded Single-Photon Sources, Luca Mazzarella, Francesco Ticozzi, Alexander V. Sergienko, Giuseppe Vallone, Paolo Villoresi

Dartmouth Scholarship

Single-photon sources represent a fundamental building block for optical implementations of quantum information tasks ranging from basic tests of quantum physics to quantum communication and high-resolution quantum measurement. In this paper, in order to compare the effectiveness of different designs, we introduce a single-photon source performance index, based on the maximum probability of generating a single photon that still guarantees a given signal-to-noise ratio. We then investigate the performance of a multiplexed system based on asymmetric configuration of multiple heralded single-photon sources. The performance and scalability comparison with both currently existing multiple-source architectures and faint laser configurations reveals an advantage …

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Measurement Of Inelastic J/Ψ And Ψ′ Photoproduction At Hera, H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, O. Arslan, V. Aushev, Y. Aushev, O. Bachynska, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, N. Bartosik, D. Bartsch, M. Basile, O. Behnke, J. Behr, U. Behrens, L. Bellagamba, A. Bertolin, S. Bhadra, M. Bindi, C. Blohm, V. Bokhonov, T. Bołd, Margarita C. K. Mattingly Aug 2013

Measurement Of Inelastic J/Ψ And Ψ′ Photoproduction At Hera, H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, O. Arslan, V. Aushev, Y. Aushev, O. Bachynska, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, N. Bartosik, D. Bartsch, M. Basile, O. Behnke, J. Behr, U. Behrens, L. Bellagamba, A. Bertolin, S. Bhadra, M. Bindi, C. Blohm, V. Bokhonov, T. Bołd, Margarita C. K. Mattingly

Faculty Publications

The cross sections for inelastic photoproduction of J/ψ and ψ′ mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb-1 collected in the period 1996-2007. The ψ′ to J/ψ cross section ratio was measured in the range 0.55 < z < 0.9 and 60 < W < 190 GeV as a function of W, z and pT. Here W denotes the photon-proton centre-of-mass energy, z is the fraction of the incident photon energy carried by the meson and p T is the transverse momentum of the meson with respect to the beam axis. The J/ψ cross sections were measured for 0.1 < z < 0.9, 60 < W < 240 GeV and pT > 1 GeV. Theoretical predictions within the non-relativistic QCD framework including NLO colour-singlet and colour-octet contributions were compared to the data, as were predictions based on the k T-factorisation approach. © 2013 SISSA.

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Supermassive Black Hole Formation At High Redshifts Via Direct Collapse: Physical Processes In The Early Stage, Jun-Hwan Choi, Isaac Shlosman, Mitchell C. Begelman Aug 2013

Supermassive Black Hole Formation At High Redshifts Via Direct Collapse: Physical Processes In The Early Stage, Jun-Hwan Choi, Isaac Shlosman, Mitchell C. Begelman

Physics and Astronomy Faculty Publications

We use numerical simulations to explore whether direct collapse can lead to the formation of supermassive black hole (SMBH) seeds at high redshifts. Using the adaptive mesh refinement code ENZO, we follow the evolution of gas within slowly tumbling dark matter (DM) halos of Mvir ~ 2 × 108 M☉ and Rvir ~ 1 kpc. For our idealized simulations, we adopt cosmologically motivated DM and baryon density profiles and angular momentum distributions. Our principal goal is to understand how the collapsing flow overcomes the centrifugal barrier and whether it is subject to fragmentation which can potentially …

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Pulse Electro-Acoustic (Pea) Measurements Of Embedded Charge Distributions, Jr Dennison, Lee H. Pearson Aug 2013

Pulse Electro-Acoustic (Pea) Measurements Of Embedded Charge Distributions, Jr Dennison, Lee H. Pearson

Presentations

No abstract provided.

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Consequences Of Cathodoluminescence For Cryogenic Applications Of Sio2-Based Space Observatory Optics And Coatings, Amberly Evans, Jr Dennison, Greg Wilson, Justin Dekany, Charles W. Bowers, Robert H. Meloy, James Heaney Aug 2013

Consequences Of Cathodoluminescence For Cryogenic Applications Of Sio2-Based Space Observatory Optics And Coatings, Amberly Evans, Jr Dennison, Greg Wilson, Justin Dekany, Charles W. Bowers, Robert H. Meloy, James Heaney

Presentations

No abstract provided.

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Diverse Electron-Induced Optical Emissions From Space Observatory Materials At Low Temperatures, Jr Dennison, Amberly Evans Jensen, Greg Wilson, Justin Dekany, Charles W. Bowers, Robert Meloy Aug 2013

Diverse Electron-Induced Optical Emissions From Space Observatory Materials At Low Temperatures, Jr Dennison, Amberly Evans Jensen, Greg Wilson, Justin Dekany, Charles W. Bowers, Robert Meloy

Presentations

No abstract provided.

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Modeling The Ionospheric E And F1 Regions: Using Sdo-Eve Observations As The Solar Irradiance Driver, Jan Josef Sojka, Joseph B. Jensen, Michael David, Robert W. Schunk, Tom Woods, Frank Eparvier Aug 2013

Modeling The Ionospheric E And F1 Regions: Using Sdo-Eve Observations As The Solar Irradiance Driver, Jan Josef Sojka, Joseph B. Jensen, Michael David, Robert W. Schunk, Tom Woods, Frank Eparvier

All Physics Faculty Publications

Over the altitude range of 90–150 km, in dayside nonauroral regions, ionization is controlled almost entirely by solar ultraviolet irradiance; the response time for ionization during solar exposure is almost instantaneous, and likewise, the time scale for recombination into neutral species is very fast when the photoionizing source is removed. Therefore, if high-resolution solar spectral data are available, along with accurate ionization cross sections as a function of wavelength, it should be possible to model this ionospheric region with greater accuracy. The Extreme Ultraviolet Variability Experiment (EVE) instrument on the National Aeronautics and Space Administration Solar Dynamics Observatory (SDO) satellite, …

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Inclusive Search For Supersymmetry Using Razor Variables In Pp Collisions At √S=7 Tev, S. A. Chatrchyan, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, W. Adam, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, H Kalakhety, Igor Vodopiyanov Aug 2013

Inclusive Search For Supersymmetry Using Razor Variables In Pp Collisions At √S=7 Tev, S. A. Chatrchyan, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, W. Adam, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, H Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

An inclusive search is presented for new heavy particle pairs produced in √s=7 TeV proton-proton collisions at the LHC using 4.7±0.1 fb -1 of integrated luminosity. The selected events are analyzed in the 2D razor space of MR, an event-by-event indicator of the heavy particle mass scale, and R, a dimensionless variable related to the missing transverse energy. The third-generation sector is probed using the event heavy-flavor content. The search is sensitive to generic supersymmetry models with minimal assumptions about the superpartner decay chains. No excess is observed in the number of events beyond that predicted by the standard model. …

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High-Order Basis Functions On Wires, Renee E. George, Dr. R. Steven Turley Aug 2013

High-Order Basis Functions On Wires, Renee E. George, Dr. R. Steven Turley

Journal of Undergraduate Research

There are many applications of physics where it is necessary to solve Maxwell’s Equations for a wave interacting with or scattering from various objects. This problem is usually impossible to solve analytically, but several cases have been solved using numerical methods. Unfortunately some cases still cannot be solved within the desired accuracy. Designers of many important applications like high frequency circuits and high-gain antennas need to use a lot of guesswork in order to produce correctly functioning devices. Our research as been aimed at implementing a new method which will permit practical numerical solutions to these problems with the desired …

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The Characteristic Frequency Of Formamidinium-Induced Noise In Gramicidin A Channels: Voltage And Concentration Dependence, Teresa Griffin Fairbanks, David D. Busath Aug 2013

The Characteristic Frequency Of Formamidinium-Induced Noise In Gramicidin A Channels: Voltage And Concentration Dependence, Teresa Griffin Fairbanks, David D. Busath

Journal of Undergraduate Research

Gramicidin A is a protein that forms cation selective ion channels in lipid bilayers (model cell membranes.) Although it is not found in natural systems, Gramicidin A is a good ion channel to study because its structure is known. It is generally thought that the passage of cations through the gramicidin channel does not cause the channel to move. Data for most cations seems to support this hypothesis. Unlike other cations, formamidinium, CH(NH2)2, causes a dramatic increase in current noise over baseline noise. This high noise level in the formamidinium channel suggests that some kind of channel movement may be …

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Modeling The Plasma In A Capillary Discharge X-Ray Laser, Dawn K. Gifford, Dr. Ross Spencer Aug 2013

Modeling The Plasma In A Capillary Discharge X-Ray Laser, Dawn K. Gifford, Dr. Ross Spencer

Journal of Undergraduate Research

The Capillary Discharge X-Ray Laser Experiment attempts to create a laser using a small capillary tube of plasma. The apparatus consists of a small soda straw-sized cylinder of gas placed between two electrodes. Approximately 25-100 kV applied across the electrodes ionizes the gas, producing a medium in which lasing can occur. The strong currents flowing through the gas create extreme conditions which are very difficult to model using typical fluid computer codes. The current Fortran code used to model the plasma fails under these conditions, so a new, more robust code is being developed. This new program is based on …

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Strengthening The Pathway To Stem Research Leadership At Hope College, Catherine Mader Aug 2013

Strengthening The Pathway To Stem Research Leadership At Hope College, Catherine Mader

Faculty Presentations

Over the past 20 years, awards from the Howard Hughes Medical Institute have supported Hope's efforts to conduct STEM research and to prepare students to pursue careers as STEM researchers. The current program is building upon prior successes to create a deliberate pathway for students as they enter Hope as novices, build STEM Researcher skills through coursework and summer research and eventually become student leaders in STEM Research groups.

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Ice And Dust In The Prestellar Dark Cloud Lynds 183: Preplanetary Matter At The Lowest Temperatures, David Horne, D. Whittet, C Poteet, J. Chiar, L. Paganini, V Bajaj, S. Shenoy, A Adamson Aug 2013

Ice And Dust In The Prestellar Dark Cloud Lynds 183: Preplanetary Matter At The Lowest Temperatures, David Horne, D. Whittet, C Poteet, J. Chiar, L. Paganini, V Bajaj, S. Shenoy, A Adamson

Physics Faculty Works

Dust grains are nucleation centers and catalysts for the growth of icy mantles in quiescent interstellar clouds, the products of which may accumulate into preplanetary matter when new stars and solar systems form within the clouds. In this paper, we present the first spectroscopic detections of silicate dust and the molecular ices H2O, CO, and CO2 in the vicinity of the prestellar core L183 (L134N). An infrared photometric survey of the cloud was used to identify reddened background stars, and we present spectra covering solid-state absorption features in the wavelength range 2-20 μm for nine of them. The mean composition …

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Visual Display Of Speech Spectra As An Aid To Lip Reading, Steven L. Tait, Dr. William J. Strong Aug 2013

Visual Display Of Speech Spectra As An Aid To Lip Reading, Steven L. Tait, Dr. William J. Strong

Journal of Undergraduate Research

Many sound pairs in the English language appear ambiguous to lip readers, such as /pa/ and /ba/ or /ki/ and /gi/. In previous studies, a lip reading aid was developed to overcome this obstacle by processing sound signals and displaying them as polygons (see Hunter, 1997 and Tait, 2000). We extended this study in the course of the research for my Honors Thesis. Different display formats were experimented with and the potential of a visual display of speech spectra was demonstrated. That research has been submitted to the Journal of the Acoustical Society of America for publication.

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Multi-Angle Reflectance Measurements Of Uranium At 584 Å, Cynthia E. Mills, Dr. R. Steven Turley Aug 2013

Multi-Angle Reflectance Measurements Of Uranium At 584 Å, Cynthia E. Mills, Dr. R. Steven Turley

Journal of Undergraduate Research

Little is known about the interaction of extreme ultraviolet light (EUV) with materials. This project is a beginning step to filling the information void. My wavelength, 584 Å, is a dominant He I line in the EUV, the 1s 2p to 1s2 transition. The electron gas model predicts that the more electrons a material has the greater its reflectance should be, which implies that U may reflect more than most substances in this region, because of its high atomic number.1 One of the obstacles to research in the EUV is that light is so readily absorbed by everything including air, …

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Oscillons And Oscillating Kinks In The Abelian-Higgs Model, V. Achilleos, F. K. Diakonos, D. J. Frantzeskakis, Garyfallia C. Katsimiga, X. N. Maintas, E. Manousakis, C. E. Tsagkarakis, A. Tsapalis Aug 2013

Oscillons And Oscillating Kinks In The Abelian-Higgs Model, V. Achilleos, F. K. Diakonos, D. J. Frantzeskakis, Garyfallia C. Katsimiga, X. N. Maintas, E. Manousakis, C. E. Tsagkarakis, A. Tsapalis

Physics Faculty Research & Creative Works

We study the classical dynamics of the Abelian Higgs model employing an asymptotic multiscale expansion method, which uses the ratio of the Higgs to the gauge field amplitudes as a small parameter. We derive an effective nonlinear Schrödinger equation for the gauge field, and a linear equation for the scalar field containing the gauge field as a nonlinear source. This equation is used to predict the existence of oscillons and oscillating kinks for certain regimes of the ratio of the Higgs to the gauge field masses. Results of direct numerical simulations are found to be in very good agreement with …

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The Quantum Mechanical Probability Current For Nonrelativistic Particles With Spin, Philip Du Toit, Dr. Jean-Francois Van Huele Aug 2013

The Quantum Mechanical Probability Current For Nonrelativistic Particles With Spin, Philip Du Toit, Dr. Jean-Francois Van Huele

Journal of Undergraduate Research

Quantum mechanics attributes to matter the properties of waves. The postulate that matter behaves as a wave and can be described by a wave function provides a mathematical description or model of many previously unexplained physical phenomena such as the diffraction pattern of an electron beam. Although the wave function itself bears no physical significance, information about all physically observable quantities is contained within the wave function. The wave functions are solutions to a quantum mechanical wave equation.

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Controlled Magnetic Reversal In Permalloy Films Patterned Into Artificial Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, B. Farmer, J. Woods, Jeffrey Todd Hastings, S. J. Lee, J. B. Ketterson, Lance E. De Long Aug 2013

Controlled Magnetic Reversal In Permalloy Films Patterned Into Artificial Quasicrystals, Vinayak Shantaram Bhat, J. Sklenar, B. Farmer, J. Woods, Jeffrey Todd Hastings, S. J. Lee, J. B. Ketterson, Lance E. De Long

Physics and Astronomy Faculty Publications

We have patterned novel Permalloy thin films with quasicrystalline Penrose P2 tilings and measured their dc magnetization and ferromagnetic resonance absorption. Reproducible anomalies in the hysteretic, low-field data signal a series of abrupt transitions between ordered magnetization textures, culminating in a smooth evolution into a saturated state. Micromagnetic simulations compare well to experimental dc hysteresis loops and ferromagnetic resonance spectra and indicate that systematic control of magnetic reversal and domain wall motion can be achieved via tiling design, offering a new paradigm of magnonic quasicrystals.

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Fluctuant Magnetism In Metal Oxide Nanocrystals Capped With Surfactants, Aaron Thurber, Michael S. Jones, Dmitri Tenne, Charles B. Hanna, Alex Punnoose Aug 2013

Fluctuant Magnetism In Metal Oxide Nanocrystals Capped With Surfactants, Aaron Thurber, Michael S. Jones, Dmitri Tenne, Charles B. Hanna, Alex Punnoose

Physics Faculty Publications and Presentations

We demonstrate experimentally that magnetism in ZnO, TiO2, CeO2, andSnO2 nanocrystals (NCs) has a fluctuant nature that varies with capping surfactant type and concentration. By developing a forced hydrolysis approach with additional postprocessing for the synthesis and surfactant capping of these NCs, we effectively avoid the influence of size, shape, and magnetic impurities on the magnetic behavior of NCs, thus revealing the systematic influence of the capping surfactants on the NC magnetism. The x-ray photoelectron spectroscopy results and theoretical calculations clearly show that the magnetism fluctuation with surfactant concentration can be attributed to the periodic …

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Biological Applications Of Extraordinary Electroconductance And Photovoltaic Effects In Inverse Extraordinary Optoconductance, Lauren C. Tran Aug 2013

Biological Applications Of Extraordinary Electroconductance And Photovoltaic Effects In Inverse Extraordinary Optoconductance, Lauren C. Tran

Arts & Sciences Graduate Student Theses and Dissertations

The Extraordinary Electroconductance (EEC) sensor has been previously demonstrated to have an electric field sensitivity of 3.05V/cm in a mesoscopic-scale structure fabricated at the center of a parallel plate capacitor. In this thesis, we demonstrate the first successful application of EEC sensors as electrochemical detectors of protein binding and biological molecule concentration. Using the avidin derivative, captavidin, in complex with the vitamin biotin, the change in four-point measured resistance with fluid protein concentration of bare EEC sensors was shown to increase by a factor of four in the presence of biomolecular binding as compared to baseline. Calculations for approximate field …

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Various Geometric Aspects Of Condensed Matter Physics, Zhenyu Zhou Aug 2013

Various Geometric Aspects Of Condensed Matter Physics, Zhenyu Zhou

Arts & Sciences Graduate Student Theses and Dissertations

Geometric aspect of condensed matter has arouse a lot of interests in recent years. The idea of Berry phase is highly appreciated in various systems. We explored the geometric features of two specific electron systems, fractional quantum Hall (FQH) states and d-wave superconducting states. For FQH states, we propose a two body operator which generates the geometric change of Laughlin state in the guiding center degrees of freedom on torus. This operator therefore generates the adiabatic evolution between Laughlin states on regular tori and the quasi-one-dimensional thin torus limit. For d-wave superconducting model, we study the local and topological features …

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Understanding Light Pollution In And Around Tucson, Arizona, Rachel K. Nydegger Aug 2013

Understanding Light Pollution In And Around Tucson, Arizona, Rachel K. Nydegger

Browse All Undergraduate research

No abstract provided.

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Homodyne Detection In A Laser Locking System, Aaron Bennett, Dr. Dallin Durfee Aug 2013

Homodyne Detection In A Laser Locking System, Aaron Bennett, Dr. Dallin Durfee

Journal of Undergraduate Research

I will discuss a high speed, low noise homodyne photo-detector. This detector will be used to better implement laser locking techniques, such as the Pound-Drever-Hall Method, that use lock-in detection. A basic explanation of the Pound-Drever-Hall method is presented in my proposal. In this report, I will discuss aspects of the detector which allow it to operate with lower noise and over a higher bandwidth than other comparable devices. I will focus this report on the difficulties that I encountered while designing this detector and the solutions that I found.

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X-Ray Diffraction Analysis Of Piezoelectric Material Pzn-Pt, Benjamin Frandsen, Dr. Branton Campbell Aug 2013

X-Ray Diffraction Analysis Of Piezoelectric Material Pzn-Pt, Benjamin Frandsen, Dr. Branton Campbell

Journal of Undergraduate Research

A wide variety of electronic devices, including microphones, acoustic transducers and high-powered microscopes, rely on a phenomenon called piezoelectricity. This is the property by which a crystal, when subjected to an electric field, experiences mechanical strain. Conversely, an applied mechanical stress produces voltage across the crystal. My research has focused on a piezoelectric material called “PZN-PT” (Lead-Zinc-Niobate Lead-Titanate), which exhibits the strongest piezoelectric response of any commercialized piezoelectric material and is currently being used for the development of next-generation electromechanical devices like those mentioned above1. The origin of the impressive properties of PZN-PT has been the topic of extensive scientific …

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Strength And Mechanical Properties Of Carbon Nanotube Templated Materials, Taylor S. Wood, Dr. Richard Vanfleet Aug 2013

Strength And Mechanical Properties Of Carbon Nanotube Templated Materials, Taylor S. Wood, Dr. Richard Vanfleet

Journal of Undergraduate Research

Carbon nanotubes have an unusually high strength-to-weight ratio and thus present an exciting material for use in reinforcing the structural integrity of microstructures. However, despite their desirable properties, carbon nanotubes have proved difficult to incorporate in materials as strengthening elements. Our group has developed a method for patterning and infiltrating, or filling, carbon nanotube forests to make structures. Infiltration proceeds by flowing an ethylene/argon mixture across a sample at a temperature of 900 °C, thus depositing amorphous carbon and locking the spaces in the nanotubes together. Using cantilever structures made of this carbon nanotube/carbon composite material, we have begun to …

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Spatial Dependence Of Magnetic Domain Memory In Exchange-Bias Films, Joseph Nelson, Dr. Karine Chesnel Aug 2013

Spatial Dependence Of Magnetic Domain Memory In Exchange-Bias Films, Joseph Nelson, Dr. Karine Chesnel

Journal of Undergraduate Research

One of the greatest challenges facing the magnetic data storage industry is the sensitivity of magnetic media to degradation by external fields. Because of this sensitivity, long-term archival data storage, which is required by law for many industries, has become very expensive to upkeep. To protect against possible degradation, most long-term archives must be removed, read, and re-recorded every few years. This process is very labor-intensive, time consuming, and expensive. This has led to the search for magnetic systems which have intrinsic magnetic domain memory, or ability of the magnetic domains within the sample to reproduce their former pattern (see …

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Cuo Deposited By Spray Pyrolosis For Use In Photovoltaics, Cary Tippets, Dr. Robert Davis Aug 2013

Cuo Deposited By Spray Pyrolosis For Use In Photovoltaics, Cary Tippets, Dr. Robert Davis

Journal of Undergraduate Research

Photovoltaics, solar cells, have great potential as an energy source. Currently solar energy is too expensive for it to make a considerable impact on the energy market. Including production and maintenance cost, solar energy is nearly five times more expensive than traditional energy sources such as coal¹. Efficiency and production costs are two aspects contributing to the cost per watt of photovoltaics. If efficiency increases or production cost decreases then the cost per watt will decrease. There are likewise two aspects of production that contribute to its cost: the cost of the absorption material, and the process by which the …

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Oh-Maser Transitions, Derek Felli Aug 2013

Oh-Maser Transitions, Derek Felli

Journal of Undergraduate Research

We looked into OH-MASER transitions considered rare in star forming regions. A MASER (Microwave Amplification by Stimulated Emission of Radiation) is emission from compact clouds of molecular gas. MASERs may consist of OH, H2O, SiO and CH3OH molecules to name some of the most common and intense. This study is helping to provide further evidence that specific OH-MASER transitions might only occur in high mass star forming regions and not low mass star forming region. If proven correct this information will be valuable in the understanding of the high and low mass star formation processes. This is helpful in describe …

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Polarization Discontinuity Induced Two-Dimensional Electron Gas At Zno/Zn(Mg)O Interfaces: A First-Principles Study, Jesuan Betancourt, J. J. Saavedra-Arias, John D. Burton, Yasuyuki Ishikawa, Evgeny Y. Tsymbal, Julian P. Velev Aug 2013

Polarization Discontinuity Induced Two-Dimensional Electron Gas At Zno/Zn(Mg)O Interfaces: A First-Principles Study, Jesuan Betancourt, J. J. Saavedra-Arias, John D. Burton, Yasuyuki Ishikawa, Evgeny Y. Tsymbal, Julian P. Velev

Evgeny Tsymbal Publications

The discovery of a high-mobility two-dimensional electron gas (2DEG) in wurtzite ZnO/Zn(Mg)O heterostructures is promising for applications due to the high mobility of the carriers. In this paper, we study the formation and properties of the 2DEG at ZnO/Zn(Mg)O interfaces using first-principles calculations based on hybrid density functional theory. The 2DEG arises from the polarization discontinuity at the interface between the two materials. The uncompensated bound charge at the interface gives rise to an electric field in the bulk of ZnO which confines free carriers close to the interface. We find that the type of the confined carriers is determined …

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