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2020

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Articles 61 - 90 of 15011

Full-Text Articles in Physical Sciences and Mathematics

Sensitivity Analysis Of An Agent-Based Simulation Model Using Reconstructability Analysis, Andey M. Nunes, Martin Zwick, Wayne Wakeland Dec 2020

Sensitivity Analysis Of An Agent-Based Simulation Model Using Reconstructability Analysis, Andey M. Nunes, Martin Zwick, Wayne Wakeland

Systems Science Faculty Publications and Presentations

Reconstructability analysis, a methodology based on information theory and graph theory, was used to perform a sensitivity analysis of an agent-based model. The NetLogo BehaviorSpace tool was employed to do a full 2k factorial parameter sweep on Uri Wilensky’s Wealth Distribution NetLogo model, to which a Gini-coefficient convergence condition was added. The analysis identified the most influential predictors (parameters and their interactions) of the Gini coefficient wealth inequality outcome. Implications of this type of analysis for building and testing agent-based simulation models are discussed.


Inventory Of Rock Glaciers In The American West And Their Topography And Climate, Allison Reese Trcka Dec 2020

Inventory Of Rock Glaciers In The American West And Their Topography And Climate, Allison Reese Trcka

Dissertations and Theses

Rock glaciers are flowing geomorphic landforms composed of an ice/debris mixture. A uniform rock glacier classification scheme was created for the western continental US, based on internationally recognized criteria, to merge the various regional published inventories. A total of 2249 rock glaciers (1564 active, 685 inactive) and 7852 features of interest were identified in 10 states (WA, OR, CA, ID, NV, UT, ID, MT, WY, CO, NM). Sulfur Creek rock glacier in Wyoming is the largest active rock glacier (2.39 km2). The mean area and elevation for active and inactive rock glaciers are 0.18 km2, 3384 …


Distributed Load Testing By Modeling And Simulating User Behavior, Chester Ira Parrott Dec 2020

Distributed Load Testing By Modeling And Simulating User Behavior, Chester Ira Parrott

LSU Doctoral Dissertations

Modern human-machine systems such as microservices rely upon agile engineering practices which require changes to be tested and released more frequently than classically engineered systems. A critical step in the testing of such systems is the generation of realistic workloads or load testing. Generated workload emulates the expected behaviors of users and machines within a system under test in order to find potentially unknown failure states. Typical testing tools rely on static testing artifacts to generate realistic workload conditions. Such artifacts can be cumbersome and costly to maintain; however, even model-based alternatives can prevent adaptation to changes in a system …


Cat Tracks – Tracking Wildlife Through Crowdsourcing Using Firebase, Tracy Ho Dec 2020

Cat Tracks – Tracking Wildlife Through Crowdsourcing Using Firebase, Tracy Ho

Master's Projects

Many mountain lions are killed in the state of California every year from roadkill. To reduce these numbers, it is important that a system be built to track where these mountain lions have been around. One such system could be built using the platform-as-a-service, Firebase. Firebase is a platform service that collects and manages data that comes in through a mobile application. For the development of cross-platform mobile applications, Flutter is used as a toolkit for developers for both iOS and Android. This entire system, Cat Tracks is proposed as a crowdsource platform to track wildlife, with the current focus …


A Multidisciplinary Approach To Investigate Deep-Pelagic Ecosystem Dynamics In The Gulf Of Mexico Following Deepwater Horizon, April Cook, Andrea Bernard, Kevin M. Boswell, Heather Bracken-Grissom Dr., Marta D'Elia, Sergio Derada, Cole Easson, David English, Ron Eytan, Tamara Frank, Chuanmin Hu, Matt Johnston, Heather Judkins, Chad Lembke, Jose Lopez, Rosanna Milligan, Jon A. Moore, Brad Penta, Nina Pruzinsky, John A. Quinlan, Travis M. Richards, Isabel C. Romero, Mahmood S. Shivji, Michael Vecchione, Max D. Weber, R.J. David Wells, Tracey Sutton Dec 2020

A Multidisciplinary Approach To Investigate Deep-Pelagic Ecosystem Dynamics In The Gulf Of Mexico Following Deepwater Horizon, April Cook, Andrea Bernard, Kevin M. Boswell, Heather Bracken-Grissom Dr., Marta D'Elia, Sergio Derada, Cole Easson, David English, Ron Eytan, Tamara Frank, Chuanmin Hu, Matt Johnston, Heather Judkins, Chad Lembke, Jose Lopez, Rosanna Milligan, Jon A. Moore, Brad Penta, Nina Pruzinsky, John A. Quinlan, Travis M. Richards, Isabel C. Romero, Mahmood S. Shivji, Michael Vecchione, Max D. Weber, R.J. David Wells, Tracey Sutton

Marine & Environmental Sciences Faculty Articles

The pelagic Gulf of Mexico (GoM) is a complex system of dynamic physical oceanography (western boundary current, mesoscale eddies), high biological diversity, and community integration via diel vertical migration and lateral advection. Humans also heavily utilize this system, including its deep-sea components, for resource extraction, shipping, tourism, and other commercial activity. This utilization has had impacts, some with disastrous consequences. The Deepwater Horizon oil spill (DWHOS) occurred at a depth of ∼1500 m (Macondo wellhead), creating a persistent and toxic mixture of hydrocarbons and dispersant in the deep-pelagic (water column below 200 m depth) habitat. In order to assess the …


Medical Marijuana And Opioids (Memo) Study: Protocol Of A Longitudinal Cohort Study To Examine If Medical Cannabis Reduces Opioid Use Among Adults With Chronic Pain, Chinazo O. Cunningham, Joanna L. Starrels, Chenshu Zhang, Marcus A. Bachhuber, Nancy L. Sohler, Frances R. Levin, Haruka Minami, Deepika E. Slawek, Julia H. Arnsten Dec 2020

Medical Marijuana And Opioids (Memo) Study: Protocol Of A Longitudinal Cohort Study To Examine If Medical Cannabis Reduces Opioid Use Among Adults With Chronic Pain, Chinazo O. Cunningham, Joanna L. Starrels, Chenshu Zhang, Marcus A. Bachhuber, Nancy L. Sohler, Frances R. Levin, Haruka Minami, Deepika E. Slawek, Julia H. Arnsten

School of Medicine Faculty Publications

Introduction In the USA, opioid analgesic use and overdoses have increased dramatically. One rapidly expanding strategy to manage chronic pain in the context of this epidemic is medical cannabis. Cannabis has analgesic effects, but it also has potential adverse effects. Further, its impact on opioid analgesic use is not well studied. Managing pain in people living with HIV is particularly challenging, given the high prevalence of opioid analgesic and cannabis use. This study's overarching goal is to understand how medical cannabis use affects opioid analgesic use, with attention to Δ9-tetrahydrocannabinol and cannabidiol content, HIV outcomes and adverse events. Methods and …


A Neat Approach To Malware Classification, Jason Do Dec 2020

A Neat Approach To Malware Classification, Jason Do

Master's Projects

Current malware detection software often relies on machine learning, which is seen as an improvement over signature-based techniques. Problems with a machine learning based approach can arise when malware writers modify their code with the intent to evade detection. This leads to a cat and mouse situation where new models must constantly be trained to detect new malware variants. In this research, we experiment with genetic algorithms as a means of evolving machine learning models to detect malware. Genetic algorithms, which simulate natural selection, provide a way for models to adapt to continuous changes in a malware families, and thereby …


The Change Of Soil Temperature To Stocking Rate On The Stipa Breviflora Desert Steppe, Jian'an Wang, Guodong Han, Yajuan Jia Dec 2020

The Change Of Soil Temperature To Stocking Rate On The Stipa Breviflora Desert Steppe, Jian'an Wang, Guodong Han, Yajuan Jia

IGC Proceedings (1997-2023)

No abstract provided.


Rotational And Continuous Grazing Of Sheep In The Inner Mongolian Steppe Of China, C. J. Wang, B. M. Tas, T. Glindemann, K. Mueller, Anna Schiborra, P. Schoenbach, M. Gierus, Friedhelm Taube, A. Susenbeth Dec 2020

Rotational And Continuous Grazing Of Sheep In The Inner Mongolian Steppe Of China, C. J. Wang, B. M. Tas, T. Glindemann, K. Mueller, Anna Schiborra, P. Schoenbach, M. Gierus, Friedhelm Taube, A. Susenbeth

IGC Proceedings (1997-2023)

No abstract provided.


Rotational Grazing Effects Of Dairy Cows On Yield And Consumption In Dwarf Napiergrass At A Paddock Scale For 3 Years From The Establishment In Southern Kyushu, Japan, A. Wadi, Yasuyuki Ishii, H. Hasyim, R. F. Utamy, Sachiko Idota, Kiichi Fukuyama Dec 2020

Rotational Grazing Effects Of Dairy Cows On Yield And Consumption In Dwarf Napiergrass At A Paddock Scale For 3 Years From The Establishment In Southern Kyushu, Japan, A. Wadi, Yasuyuki Ishii, H. Hasyim, R. F. Utamy, Sachiko Idota, Kiichi Fukuyama

IGC Proceedings (1997-2023)

No abstract provided.


Prediction Of Diet Quality In Mongolian Livestock With Portable Near Infrared Spectroscopy Offeces, G. Tolleson, G. Udval, S. Prince, K. Banik Dec 2020

Prediction Of Diet Quality In Mongolian Livestock With Portable Near Infrared Spectroscopy Offeces, G. Tolleson, G. Udval, S. Prince, K. Banik

IGC Proceedings (1997-2023)

No abstract provided.


The Sets Of Julia And Mandelbrot For Multi-Dimensional Case Of Logistic Mapping, Rasul Ganikhodzhaev, Shavkat Seytov, Islombek Obidjonov, Lazizbek Sadullayev Dec 2020

The Sets Of Julia And Mandelbrot For Multi-Dimensional Case Of Logistic Mapping, Rasul Ganikhodzhaev, Shavkat Seytov, Islombek Obidjonov, Lazizbek Sadullayev

Central Asian Problems of Modern Science and Education

The present paper is devoted to investigation of the multidimensional case of the logistic mapping on the plane to itself. In this paper we learnt the properties of the sets of Julia and Mandelbrot for some two-dimensional logistic mappings. The sets of Julia and Mandelbrot help to define asymptotical behavior of the trajectories of certain mappings. The analytical solutions of the equations for finding fixed and periodic points and the computational simulations for describing the sets of Julia and Mandelbrot are the main results of this paper.


Cosine Similarity And Its Implementation To Uzbek Language Data, Sanatbek Gayratovich Matlatipov Dec 2020

Cosine Similarity And Its Implementation To Uzbek Language Data, Sanatbek Gayratovich Matlatipov

Central Asian Problems of Modern Science and Education

In this article, it has been considered the cosine similarity and its application to search for similarities in the Uzbek language texts. The algorithm of cosine similarity has been used to determine similarity of Uzbek texts. We give the application of the program, proposed by the authors, to the texts of the educational portal ziyonet.uz dataset;


Marine Geobiology Ocg 502, Joanna Burkhardt Dec 2020

Marine Geobiology Ocg 502, Joanna Burkhardt

Library Impact Statements

No abstract provided.


Global Ocean Change Ocg 511, Joanna Burkhardt Dec 2020

Global Ocean Change Ocg 511, Joanna Burkhardt

Library Impact Statements

No abstract provided.


Marine Geobiology Ocg 5xx, Joanna Burkhardt Dec 2020

Marine Geobiology Ocg 5xx, Joanna Burkhardt

Library Impact Statements

No abstract provided.


Near Conformal Perturbation Theory In Syk Type Models, Sumit R. Das, Animik Ghosh, Antal Jevicki, Kenta Suzuki Dec 2020

Near Conformal Perturbation Theory In Syk Type Models, Sumit R. Das, Animik Ghosh, Antal Jevicki, Kenta Suzuki

Physics and Astronomy Faculty Publications

We present a systematic procedure to extract the dynamics of the low energy soft mode in SYK type models with a single energy scale J and emergent reparametrization symmetry in the IR. This is given in the framework of the perturbative scheme of arXiv:1608.07567 based on a specific (off-shell) breaking of conformal invariance in the UV, adjusted to yield the exact large-N saddle point. While this breaking term formally vanishes on-shell, it has a non-trivial effect on correlation functions and the effective action. In particular, it leads to the Schwarzian action with a specific coupling to bi-local matter. The …


Synergistic Effect Of Dissolving O2 And Wavelength On The Photo-Assisted Anodic Deposition Of Ceo2 Thin Films, Tong-Zheng Jin, Yu-Meng Yang, Sheng-Hui Fan, Guo-Ying Wei, Zhao Zhang Dec 2020

Synergistic Effect Of Dissolving O2 And Wavelength On The Photo-Assisted Anodic Deposition Of Ceo2 Thin Films, Tong-Zheng Jin, Yu-Meng Yang, Sheng-Hui Fan, Guo-Ying Wei, Zhao Zhang

Journal of Electrochemistry

Cerium dioxide (CeO2) thin films have been applied as new material in many technical fields such as solid oxide fuel cells, catalysts, UV absorbents, pharmacology, and coatings for corrosion protection of many metals and alloys. Electrodeposition is widely considered to be one of the best preparation methods for CeO2 film. In this work, the CeO2 films were prepared by photo-assisted anodic deposition in the bath solutions containing 0.05 mol·L-1 cerium (III) nitrate, 0.1 mol·L-1 ammonia acetate and 70% (V/V) ethanol onto 316L stainless steel (SS) surface. The synergistic effects of three monochromatic …


Pyxtal_Ff: A Python Library For Automated Force Field Generation, Howard Yanxon, David Zagaceta, Binh Tang, David S. Matteson, Qiang Zhu Dec 2020

Pyxtal_Ff: A Python Library For Automated Force Field Generation, Howard Yanxon, David Zagaceta, Binh Tang, David S. Matteson, Qiang Zhu

Physics & Astronomy Faculty Research

We present PyXtal_FF—a package based on Python programming language—for developing machine learning potentials (MLPs). The aim of PyXtal_FF is to promote the application of atomistic simulations through providing several choices of atom-centered descriptors and machine learning regressions in one platform. Based on the given choice of descriptors (including the atom-centered symmetry functions, embedded atom density, SO4 bispectrum, and smooth SO3 power spectrum), PyXtal_FF can train MLPs with either generalized linear regression or neural network models, by simultaneously minimizing the errors of energy/forces/stress tensors in comparison with the data from ab-initio simulations. The trained MLP model from PyXtal_FF is interfaced with …


Preparation And Process Optimization Of Cathode Materials For Lithium-Sulfur Batteries, Kai Wu Dec 2020

Preparation And Process Optimization Of Cathode Materials For Lithium-Sulfur Batteries, Kai Wu

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries represent promising candidates for next-generation energy storage system due to their high energy density and low material cost. However, the industrial application of Li-S batteries remains challenges because of the shuttle effect from lithium polysulfides and the lack of facial routes for Li-S battery preparation. To solve these problems, a cathode consisting of different commercial carbon materials, namely, acetylene black (SP), Ketjen Black (KB) and carbon nanotube (CNT), with sulfur (S) is prepared separately for Li-S battery. After the process of 8-h ball milling for KB/S composite, together with the polyvinyl pyrrolidone (PVP) binder, the cathode could …


Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling, Cun Wang, Wei-Jiang Zhang, Teng-Fei He, Bo Lei, You-Jie Shi, Yao-Dong Zheng, Wei-Lin Luo, Fang-Ming Jiang Dec 2020

Degradation And Thermal Characteristics Of Lini0.8Co0.15Al0.05O2/Graphite Lithium Ion Battery After Different State Of Charge Ranges Cycling, Cun Wang, Wei-Jiang Zhang, Teng-Fei He, Bo Lei, You-Jie Shi, Yao-Dong Zheng, Wei-Lin Luo, Fang-Ming Jiang

Journal of Electrochemistry

The LiNi0.8Co0.15Al0.05O2 (NCA) cathode exhibits high energy density and large reversible capacity, which plays an essential role in the field of electric vehicles (EVs). However, low capacity retention and poor thermal stability limit its application. Few literatures are found for the capacity degradation mechanism of NCA/graphite batteries at home and abroad. The different state of charge (SOC) ranges cycle degradation behaviors of 18650-type NCA/graphite (2.4 Ah) battery were studied in this paper. The SOC ranges considered were 0% ~ 20% (low), 20% ~ 70% (medium), 70% ~ 100% (high), and 0% ~ 100% …


Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite, Ming-Tao Duan, Yan-Shuang Meng, Hong-Shuai Zhang Dec 2020

Preparations And Sodium Storage Properties Of Ni3S2@Cnt Composite, Ming-Tao Duan, Yan-Shuang Meng, Hong-Shuai Zhang

Journal of Electrochemistry

Transition metal sulfides (TMSs)-based electrode materials with highly reversible sodium storage have attracted extensive attentions as one of the most prospective electrode materials for sodium ion batteries (SIBs). However, low cycling stability and rate property caused by large volume expansion and poor electronic conductivity during the electrochemical reaction still hamper their further practical application. In this work, in-situ encapsulated Ni3S2 nanoparticles in carbon nanotubes (Ni3S2@CNT) have been successfully fabricated as an anode material for high-performance SIBs by a one-step solid-phase calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), …


Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries, Pin-Song Chen, Yi-Tao Hu, Xin-Yi Zhang, Pei-Kang Shen Dec 2020

Effect Of Stereotaxically-Constructed Graphene On The Negative Electrode Performance Of Lead-Acid Batteries, Pin-Song Chen, Yi-Tao Hu, Xin-Yi Zhang, Pei-Kang Shen

Journal of Electrochemistry

With the advantages of high ratio surface area, excellent conductivity and high stability, the stereotaxically-constructed graphene (SCG) material was added to the negative active material (NAM) of lead-acid battery for improving battery performance. XRD, SEM and cyclic voltammetry tests were carried out to analyze the influence of SCG on negative active material. It is found that the conversion efficiency of lead sulfate to lead in the negative active material added with SCG material was higher than that of control group, and the particle size of the lead sulfate obtained after the discharge reaction was smaller, which are favorable factors for …


Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction, Chang Zhu, Wei Chen, Yan-Fang Song, Xiao Dong, Gui-Hua Li, Wei Wei, Yu-Han Sun Dec 2020

Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction, Chang Zhu, Wei Chen, Yan-Fang Song, Xiao Dong, Gui-Hua Li, Wei Wei, Yu-Han Sun

Journal of Electrochemistry

Electrochemical conversion of carbon dioxide (CO2) driven by renewable electricity that can meet both carbon emission reduction and renewable energy utilization has been rapidly developed in recent years. Copper (Cu) catalyst has long been a promising candidate for CO2 electroreduction applications because of its natural abundance and specific capability of producing a substantial amount of C2 products. However, various metallic Cu electrodes reported have been significantly influenced by the adsorption of certain cation/anion ions, resulting in wide-span catalytic activities and selectivity for various products. In addition, a recent report demonstrated that by virtue of gas-diffusion flow cell …


Preparations And Properties Of Low Cost Sulfide Solid Electrolytes Li6-XPs5-XClX, Na-Chuan Yang, Yu Wang, Yi Shuai, Kang-Hua Chen Dec 2020

Preparations And Properties Of Low Cost Sulfide Solid Electrolytes Li6-XPs5-XClX, Na-Chuan Yang, Yu Wang, Yi Shuai, Kang-Hua Chen

Journal of Electrochemistry

With the shortage of energy and environmental pollution, the storage of electric energy is getting more attention all over the world. In order to improve the energy density and safety performance of batteries, uses of solid electrolyte become more and more popular. However, because the conductivity of solid electrolyte is not comparable to that of liquid electrolyte, the solid electrolyte application has certain limitations. With the efforts of researchers from various countries, there are several different solid electrolytes having better conductivity, for instance, sulfide solid electrolyte and oxide solid electrolyte. Sulfide solid electrolyte is a highly promising solid electrolyte material …


Step-By-Step Modification Of Graphite Felt Electrode For Vanadium Redox Flow Battery, Jing-Yuan Lou, Dong-Jiang You, Xue-Jing Li Dec 2020

Step-By-Step Modification Of Graphite Felt Electrode For Vanadium Redox Flow Battery, Jing-Yuan Lou, Dong-Jiang You, Xue-Jing Li

Journal of Electrochemistry

As a well-known electrode material of the vanadium redox flow battery (VRFB),graphite felt electrode is the frequently-used electrode material in VRFB, and its low electrochemical activity is one of the key factors for the low power density of VRFB. In this work, we proposed a step-by-step modification method, which used KMnO4 to oxidize graphite felt first and then placed in an activation solution to excite its reactivity, to improve the electrochemical performance of the graphite felt electrode. According to the results from cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) characterizations …


Pitting Behaviors Of Passivated And Trans-Passivated 304 Stainless Steel, Jing Shen, Zi-Ming Wang, Da-Jiang Zheng, Guang-Ling Song Dec 2020

Pitting Behaviors Of Passivated And Trans-Passivated 304 Stainless Steel, Jing Shen, Zi-Ming Wang, Da-Jiang Zheng, Guang-Ling Song

Journal of Electrochemistry

In order to further understand the passivation and trans-passivation behaviors of 304 stainless steels, the samples were pretreated under different polarization potentials and their corrosion behaviors were investigated. It was found that the pitting potential of the untreated sample was the same as that of the sample treated with 1.1 V trans-passivation potential, while the pitting potential of the sample treated with 0.5 V passivation treatment was the highest. This observation was further verified by the SKP results. According to SEM observations, the surface of the untreated sample preserved a polishing morphology, while the surface of the 0.5 V passivation …


Effect Of 18-Crown-6 Additive On Chromium Electrodeposition In Ionic Liquid, Yi-Jie Wang, Dong-Fang Niu, Xin-Sheng Zhang Dec 2020

Effect Of 18-Crown-6 Additive On Chromium Electrodeposition In Ionic Liquid, Yi-Jie Wang, Dong-Fang Niu, Xin-Sheng Zhang

Journal of Electrochemistry

Trivalent chromium ion (Cr3+) is used for electrodeposition due to its low toxicity. Electrodeposition in ionic liquids can greatly solve for hydrogen evolution problem. However,as a widely used Cr(III) precursor, chromium chloride hydrate (CrCl3·6H2O), still contains water. In the presence of water, Cr3+ will form a complex coordination structure with water molecules ([Cr(H2O)6]3+), which is a stable octahedral structure and is difficult to be directly reduced to chromium metal. Therefore, coordination agents should be added into the bath. In this work, the effect of 18-Crown-6 additive on chromium electrodeposition was investigated in …


Electrochemical Determination Of Dopamine Based On Metal-Substituted Polyoxometalates Composites, Yi-Fei Xing, Na Li, Xiao-Fang Wen, Hong-Yan Han, Min Cui, Cong Zhang, Ju-Jie Ren, Xue-Ping Ji Dec 2020

Electrochemical Determination Of Dopamine Based On Metal-Substituted Polyoxometalates Composites, Yi-Fei Xing, Na Li, Xiao-Fang Wen, Hong-Yan Han, Min Cui, Cong Zhang, Ju-Jie Ren, Xue-Ping Ji

Journal of Electrochemistry

In this report, a dopamine electrochemical sensor based on metal-substituted polyoxometalates and reduced graphene oxide (RGO) composite was successfully constructed. The K2H2SiW11NiO39·xH2O (SiW11Ni) was synthesized by hydrothermal method, while the RGO was prepared by Hummers' method and chemical reduction method. The above-mentioned materials were characterized by SEM, FTIR and XRD. The as-synthesized SiW11Ni and RGO composites were modified on the surface of glassy carbon electrode (GCE) by drop coating method, and the sensing interface (SiW11Ni-RGO/GCE) was successfully constructed. The electrochemical properties of …


Local Electronic And Magnetic Properties Of The Doped Topological Insulators Bi₂Se₃:Ca And Bi₂Te₃:Mn Investigated Using Ion-Implanted ⁸Li Β-Nmr, Ryan M. L. Mcfadden, Aris Chatzichristos, David L. Cortie, Derek Fujimoto, Yew San Hor, Huiwen Ji, Victoria L. Karner, For Full List Of Authors, See Publisher's Website. Dec 2020

Local Electronic And Magnetic Properties Of The Doped Topological Insulators Bi₂Se₃:Ca And Bi₂Te₃:Mn Investigated Using Ion-Implanted ⁸Li Β-Nmr, Ryan M. L. Mcfadden, Aris Chatzichristos, David L. Cortie, Derek Fujimoto, Yew San Hor, Huiwen Ji, Victoria L. Karner, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report β-NMR measurements in Bi2Se3:Ca and Bi2Te3:Mn single crystals using 8Li+ implanted to depths on the order of 100 nm. Above ∼200K, spin-lattice relaxation reveals diffusion of 8Li+, with activation energies of ∼0.4eV (∼0.2eV) in Bi2Se3:Ca (Bi2Te3:Mn). At lower temperatures, the NMR properties are those of a heavily doped semiconductor in the metallic limit, with Korringa relaxation and a small, negative, temperature-dependent Knight shift in Bi2Se3:Ca. From this, we make a detailed comparison with …