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2007

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Articles 1 - 30 of 30

Full-Text Articles in Atomic, Molecular and Optical Physics

Fabrication Of Robust Superconducting Granular Aluminium/Palladium Bilayer Microbolometers With Sub-Nanosecond Response, Thomas E. Wilson Dec 2007

Fabrication Of Robust Superconducting Granular Aluminium/Palladium Bilayer Microbolometers With Sub-Nanosecond Response, Thomas E. Wilson

Physics Faculty Research

We provide a convenient recipe for fabricating reliable superconducting microbolometers as acoustic phonon detectors with sub-nanosecond response, using imagereversal optical lithography and dc-magnetron sputtering, and our recipe requires no chemical or plasma etching. Our approach solves the traditional problem for granular aluminium bolometers of unreliable (i.e., non-Ohmic) electrical contacts by sequentially sputtering the granular aluminium film and then a palladium capping layer. We use dc calibration data, the method of Danilchenko et al. [1], and direct nanosecond-pulsed photoexcitation to obtain the microbolometer’s characteristic current, thermal conductance, characteristic relaxation time, and heat capacity. We also demonstrate the use of the deconvolution …

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Decomposition-Based Recovery Of Absorbers In Turbid Media, S D. Campbell, I L. Goodin, S D. Grobe, Qichang Su, Rainer Grobe Dec 2007

Decomposition-Based Recovery Of Absorbers In Turbid Media, S D. Campbell, I L. Goodin, S D. Grobe, Qichang Su, Rainer Grobe

Faculty publications – Physics

We suggest that the concept of the point-spread function traditionally used to predict the blurred image pattern of various light sources embedded inside turbid media can be generalized under certain conditions to predict also the presence and location of spatially localized absorbing inhomogeneities based on shadow point-spread functions associated with each localized absorber in the medium. The combined image obtained from several absorbers can then be decomposed approximately into the arithmetic sums of these individual shadow point-spread functions with suitable weights that can be obtained from multiple-regression analysis. This technique permits the reconstruction of the location of absorbers.

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Practical Sensor For Measurement Of Nitrogen, Dusan Popovic, Vladimir Milosavljevic, Steven Daniels Nov 2007

Practical Sensor For Measurement Of Nitrogen, Dusan Popovic, Vladimir Milosavljevic, Steven Daniels

Articles

This paper presents a method for precise measurement of atomic and molecular nitrogen in an oxygen-nitrogen dc plasma. This is achieved by monitoring the intensities of the atomic nitrogen spectral line at 821.6 nm and the molecular nitrogen bandhead at 337.1 nm, relative to the atomic oxygen spectral line at 844.7 nm. Oxygen is one of the most frequently used gases for surface chemical treatment, including deposition and etching, therefore the ability to measure and control the process and chemical composition of the process is essential. To validate this oxygen actimometry method for N2-xO2 (where x varies from 0 to …

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Higher-Order Threshold Corrections For Single Top Quark Production, Nikolaos Kidonakis Sep 2007

Higher-Order Threshold Corrections For Single Top Quark Production, Nikolaos Kidonakis

Faculty and Research Publications

I discuss single top quark production at the Tevatron and the LHC. The cross section, including soft-gluon threshold corrections through NNNLO, is presented for each partonic channel. The higher-order corrections provide significant contributions to the single top cross sections at both colliders.

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On The Time-Resolved Optogalvanic Spectra Of Neon And Krypton, Naveed Piracha, K. Nesbett, S. Moten, P. Moeller Aug 2007

On The Time-Resolved Optogalvanic Spectra Of Neon And Krypton, Naveed Piracha, K. Nesbett, S. Moten, P. Moeller

Naveed K. Piracha

In this work time resolved optogalvanic signals associated with transitions excited from the first metastable state of neon and krypton have been studied. These gases have similar energy state configurations and it is of significant interest to study their time resolved optogalvanic waveforms resulting from transitions belonging to the states of same quantum numbers. The experimentally observed optogalvanic signals recorded for different discharge currents have been fitted to a theoretical model to obtain parameters that determine amplitudes, instrumental time constants and decay rates of the 1s levels.

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Classical-Quantum Correspondence In Electron-Positron Pair Creation, N I. Chott, Qichang Su, Rainer Grobe Jul 2007

Classical-Quantum Correspondence In Electron-Positron Pair Creation, N I. Chott, Qichang Su, Rainer Grobe

Faculty publications – Physics

We examine the creation of electron-positron pairs in a very strong force field. Using numerical solutions to quantum field theory we calculate the spatial and momentum probability distributions for the created particles. A comparison with classical mechanical phase space calculations suggests that despite the fully relativistic and quantum mechanical nature of the matter creation process, most aspects can be reproduced accurately in terms of classical mechanics.

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Optical Absorption, Depolarization, And Scatter Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond At 1.064 Μm, Giorgio Turri, Ying Chen, Michael Bass Jun 2007

Optical Absorption, Depolarization, And Scatter Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond At 1.064 Μm, Giorgio Turri, Ying Chen, Michael Bass

Publications

No abstract provided.

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Optical Properties Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond, Giorgio Turri, Ying Chen, Michael Bass, David Orchard, James E. Butler May 2007

Optical Properties Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond, Giorgio Turri, Ying Chen, Michael Bass, David Orchard, James E. Butler

Publications

Epitaxial single-crystal chemical-vapor-deposited diamond was obtained from Element Six Ltd. (Ascot, UK) and from Apollo Diamond (Boston, MA). Both companies provided 5 x 5 mm squares with thicknesses ranging from 0.5 to 1.5 mm. In addition, Element Six provided 10-mm-diameter disks with a thickness of 1.0 mm. The absorptance of all specimens at 1064 nm was measured by laser calorimetry, with good agreement between independent measurements at the University of Central Florida and at QinetiQ (Malvern, UK). Depolarization at 1064 nm and ultraviolet absorption properties are also reported.

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Velocity Half-Sphere Model For Multiple Scattering In A Semi-Infinite Medium, S Menon, Q Su, Rainer Grobe May 2007

Velocity Half-Sphere Model For Multiple Scattering In A Semi-Infinite Medium, S Menon, Q Su, Rainer Grobe

Faculty publications – Physics

We show how the velocity half-sphere model [S. Menon, Q. Su, and R. Grobe, Phys. Rev. E 72, 041910 (2005)] recently introduced to predict the propagation of light for an infinite turbid medium can be extended to account for the emission of multiply scattered light for a geometry with a planar boundary. A comparison with exact solutions obtained from Monte Carlo simulations suggests that this approach can improve the predictions of the usual diffusion theory for both isotropic and highly forward scattering media with reflecting interfaces.

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Higher-Order Soft Gluon Corrections In Single Top Quark Production At The Cern Lhc, Nikolaos Kidonakis Apr 2007

Higher-Order Soft Gluon Corrections In Single Top Quark Production At The Cern Lhc, Nikolaos Kidonakis

Faculty and Research Publications

I present a calculation of soft-gluon corrections to single top-quark production in pp collisions at the LHC via the standard model partonic processes in the t and s channels and associated top quark and W boson production. Higher-order soft-gluon corrections through next-to-next-to-next-to-leading order (NNNLO) are calculated at next-to-leading logarithmic (NLL) accuracy. The soft-gluon corrections in the s channel and in tW production are large and dominant, while in the t channel they are not a good approximation of the complete QCD corrections.

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Simulation And Analysis Of Ultrafast Laser Pulse Induced Plasma Generation In Dielectric Materials, Jeremy Gulley, Sebastian Winkler, William Dennis Mar 2007

Simulation And Analysis Of Ultrafast Laser Pulse Induced Plasma Generation In Dielectric Materials, Jeremy Gulley, Sebastian Winkler, William Dennis

Jeremy R. Gulley

Recent experiments on optical damage by ultrashort laser pulses have demonstrated that the temporal pulseshape can dramatically influence plasma generation in fused silica and sapphire. In this work a modified 3+1D nonlinear Schroedinger equation for the pulse propagation coupled to a rate equation for the plasma density in the dielectric material is used to simulate pulse propagation and plasma formation in a range of dielectric materials. We use these simulations to analyze the influence of pulse-width, pulse-shape and beam geometry on the formation of the electron plasma and hence damage in the bulk material. In particular, when possible, we simulate …

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Nonlocal Entanglement Of Coherent States, Complementarity, And Quantum Erasure, Christopher C. Gerry, Rainer Grobe Mar 2007

Nonlocal Entanglement Of Coherent States, Complementarity, And Quantum Erasure, Christopher C. Gerry, Rainer Grobe

Faculty publications – Physics

We describe a nonlocal method for generating entangled coherent states of a two-mode field wherein the field modes never meet. The proposed method is an extension of an earlier proposal [C. C. Gerry, Phys. Rev. A 59, 4095 (1999)] for the generation of superpositions of coherent states. A single photon injected into a Mach-Zehnder interferometer with cross-Kerr media in both arms coupling with two external fields in coherent states produces entangled coherent states upon detection at one of the output ports. We point out that our proposal can be alternatively viewed as a "which path" experiment, and in the case …

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Ground State Structures And Photoelectron Spectroscopy Of [Com(Coronene)]− Complexes, Anil K. Kandalam, Boggavarapu Kiran, Puru Jena, Xiang Li, Andrej Grubisic, Kit H. Bowen Feb 2007

Ground State Structures And Photoelectron Spectroscopy Of [Com(Coronene)]− Complexes, Anil K. Kandalam, Boggavarapu Kiran, Puru Jena, Xiang Li, Andrej Grubisic, Kit H. Bowen

Physics & Engineering Faculty Publications

No abstract provided.

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Focusing Capillary Optics For Use In Solution Small-Angle X-Ray Scattering, Jessica S. Lamb, Sterling Cornaby, Kurt Andresen, Lisa W. Kwok, Hye Yoon Park, Xiangyun Qiu, Detlef-M. Smilgies, Donald H. Bilderback, Lois Pollack Feb 2007

Focusing Capillary Optics For Use In Solution Small-Angle X-Ray Scattering, Jessica S. Lamb, Sterling Cornaby, Kurt Andresen, Lisa W. Kwok, Hye Yoon Park, Xiangyun Qiu, Detlef-M. Smilgies, Donald H. Bilderback, Lois Pollack

Physics and Astronomy Faculty Publications

Measurements of the global conformation of macromolecules can be carried out using small-angle X-ray scattering (SAXS). Glass focusing capillaries, manufactured at the Cornell High Energy Synchrotron Source (CHESS), have been successfully employed for SAXS measurements on the heme protein cytochrome c. These capillaries provide high X-ray flux into a spot size of tens of micrometres, permitting short exposures of small-volume samples. Such a capability is ideal for use in conjunction with microfluidic mixers, where time resolution may be determined by beam size and sample volumes are kept small to facilitate mixing and conserve material.

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Synthesize A Nanoscale Ferrofluid, Rob Snyder Jan 2007

Synthesize A Nanoscale Ferrofluid, Rob Snyder

Nanotechnology Teacher Summer Institutes

The chemical synthesis of a ferrofluid is a nanoscale science activity that originally appears in the Journal of Chemical Education. Access to the following website requires a subscription to the journal. J. Chem. Educ., 76, 943-948 (1999). The article was authored by Jonathan Breitzer and George Lisensky.

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Phase Diagram Of The One-Dimensional Hubbard-Holstein Model At Half And Quarter Filling, Rahul Hardikar, R. T. Clay Jan 2007

Phase Diagram Of The One-Dimensional Hubbard-Holstein Model At Half And Quarter Filling, Rahul Hardikar, R. T. Clay

Scholarship and Professional Work - LAS

The Hubbard-Holstein model is one of the simplest to incorporate both electron-electron and electron-phonon interactions. In one dimension at half filling, the Holstein electron-phonon coupling promotes on-site pairs of electrons and a Peierls charge-density wave, while the Hubbard on-site Coulomb repulsion U promotes antiferromagnetic correlations and a Mott insulating state. Recent numerical studies have found a possible third intermediate phase between Peierls and Mott states. From direct calculations of charge and spin susceptibilities, we show that (i) as the electron-phonon coupling is increased, first a spin gap opens, followed by the Peierls transition. Between these two transitions, the metallic intermediate …

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Low-Energy Electron Capture By 6-Aza-2-Thiothymine: Investigations By Electron Attachment And Electron Transmission Spectroscopies, Stanislav A. Pshenichnyuk, Gordon A. Gallup, Paul Burrow Jan 2007

Low-Energy Electron Capture By 6-Aza-2-Thiothymine: Investigations By Electron Attachment And Electron Transmission Spectroscopies, Stanislav A. Pshenichnyuk, Gordon A. Gallup, Paul Burrow

Paul Burrow Publications

The interaction of low-energy (0-10 eV) electrons with 6-aza-2-thiothymine is investigated in the gas phase by studies of sharp structure in the total electron scattering cross section and by mass analysis of the stable or long-lived negative ions produced by electron attachment. The most efficient fragmentation process, occurring at 0.15 eV, involves the ejection of a closed-shell neutral molecule (CH3CN). Ab initio calculations support our proposal that this process leads to ring closure to form a stable four-member heterocyclic anion. A long-lived parent anion with an approximate lifetime of 75 microseconds is observed near zero electron energy, and …

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Diffusion And Fractional Diffusion Based Models For Multiple Light Scattering And Image Analysis, Jonathan Blackledge Jan 2007

Diffusion And Fractional Diffusion Based Models For Multiple Light Scattering And Image Analysis, Jonathan Blackledge

Articles

This paper considers a fractional light diffusion model as an approach to characterizing the case when intermediate scattering processes are present, i.e. the scattering regime is neither strong nor weak. In order to introduce the basis for this approach, we revisit the elements of formal scattering theory and the classical diffusion problem in terms of solutions to the inhomogeneous wave and diffusion equations respectively. We then address the significance of these equations in terms of a random walk model for multiple scattering. This leads to the proposition of a fractional diffusion equation for modelling intermediate strength scattering that is based …

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Design And Performance Of A Curved-Crystal X-Ray Emission Spectrometer, A. C. Hudson, Wayne C. Stolte, Dennis W. Lindle, Renaud Guillemin Jan 2007

Design And Performance Of A Curved-Crystal X-Ray Emission Spectrometer, A. C. Hudson, Wayne C. Stolte, Dennis W. Lindle, Renaud Guillemin

Chemistry and Biochemistry Faculty Research

A curved-crystal x-ray emission spectrometer has been designed and built to measure 2–5 keV x-ray fluorescence resulting from a core-level excitation of gas phase species. The spectrometer can rotate 180°, allowing detection of emitted x rays with variable polarization angles, and is capable of collecting spectra over a wide energy range (20 eV wide with 0.5 eV resolution at the Cl K edge) simultaneously. In addition, the entire experimental chamber can be rotated about the incident-radiation axis by nearly 360° while maintaining vacuum, permitting measurements of angular distributions of emitted x rays.

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Anisotropic Magnetoresistance In Colossal Magnetoresistive La1−Xsrxmno3 Thin Films, Jeng-Bang Yau, X. Hong, A. Posadas, C. H. Ahn, W. Gao, E. Altman, Y. Bason, L. Klein, M. Sidorov, Z. Krivokapic Jan 2007

Anisotropic Magnetoresistance In Colossal Magnetoresistive La1−Xsrxmno3 Thin Films, Jeng-Bang Yau, X. Hong, A. Posadas, C. H. Ahn, W. Gao, E. Altman, Y. Bason, L. Klein, M. Sidorov, Z. Krivokapic

Xia Hong Publications

We report on magnetic field and temperature-dependent measurements of the anisotropic magnetoresistance (AMR) in epitaxial La1−xSrxMnO3 (LSMO) thin films. While in 3d ferromagnetic alloys increasing the magnetization, either by reducing the temperature or increasing the magnetic field, increases the AMR, we find that in LSMO films the AMR dependence on magnetization displays nonmonotonic behavior which becomes particularly pronounced in lightly doped compounds. We believe that this behavior is related to the inhomogeneity exhibited by these materials.

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Planar Hall Effect In Epitaxial Thin Films Of Magnetite, Y. Bason, L. Klein, H. Q. Wang, J. Hoffman, X. Hong, V. E. Henrich, C. H. Ahn Jan 2007

Planar Hall Effect In Epitaxial Thin Films Of Magnetite, Y. Bason, L. Klein, H. Q. Wang, J. Hoffman, X. Hong, V. E. Henrich, C. H. Ahn

Xia Hong Publications

We measured the planar Hall effect (PHE) of magnetite (Fe3O4) films between 150 and 350 K. The PHE was measured both with a constant magnetic field rotating in the plane of the sample and in a remanent state after applying a field in specific directions. The PHE amplitude decreases with temperature; however, it changes little between 300 and 350 K. The remanent PHE signal is as high as 10 V/A, larger than previously observed in manganite films. We also measured the PHE in the remanent state and found that its magnitude and stability make it a …

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A Relation Between Energies Of The Short-Lived Negative Ion States And Energies Of Unfilled Molecular Orbitals For A Series Of Bromoalkanes, S. A. Pshenichnyuk, N. L. Asfandiarov, Paul Burrow Jan 2007

A Relation Between Energies Of The Short-Lived Negative Ion States And Energies Of Unfilled Molecular Orbitals For A Series Of Bromoalkanes, S. A. Pshenichnyuk, N. L. Asfandiarov, Paul Burrow

Paul Burrow Publications

A series of bromoalkanes was investigated by means of electron transmission spectroscopy in the gas phase. Experimental values of vertical electron affinities associated with occupation of the LUMO by an incoming electron were assigned using ab initio quantum chemical calculations. The predicted vertical electron affinity values differ from measured ones by at most ±0.2 eV.

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Magnetic Enhancement In Cobalt-Manganese Alloy Clusters, Shuangye Yin, Ramiro Moro, Xiaoshan Xu, Walter A. De Heer Jan 2007

Magnetic Enhancement In Cobalt-Manganese Alloy Clusters, Shuangye Yin, Ramiro Moro, Xiaoshan Xu, Walter A. De Heer

Xiaoshan Xu Papers

Magnetic moments of CoNMnM and CoNVM clusters (N ≤ 60; M ≤ N/3) are measured in molecular beams using the Stern-Gerlach deflection method. Surprisingly, the per atom average moments of CoNMnM clusters are found to increase with Mn concentration, in contrast to bulk CoMn. The enhancement with Mn doping is found to be independent of cluster size and composition in the size range studied. Meanwhile, CoNVM clusters show reduction of average moments with increasing V doping, consistent with what is expected in bulk CoV. The results are …

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Formation Of In- (2×1) And In Islands On Si (100) - (2×1) By Femtosecond Pulsed Laser Deposition, M. A. Hafez, H. E. Elsayed-Ali Jan 2007

Formation Of In- (2×1) And In Islands On Si (100) - (2×1) By Femtosecond Pulsed Laser Deposition, M. A. Hafez, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The growth of indium on a vicinal Si (100) - (2×1) surface at room temperature by femtosecond pulsed laser deposition (fsPLD) was investigated by in situ reflection high-energy electron diffraction (RHEED). Recovery of the RHEED intensity was observed between laser pulses and when the growth was terminated. The surface diffusion coefficient of deposited In on initial two-dimensional (2D) In- (2×1) layer was determined. As growth proceeds, three-dimensional In islands grew on the 2D In- (2×1) layer. The RHEED specular profile was analyzed during film growth, while the grown In islands were examined by ex situ atomic force microscopy. The full …

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Unitary And Nonunitary Approaches In Quantum Field Theory, K D. Lamb, Christopher C. Gerry, Rainer Grobe Jan 2007

Unitary And Nonunitary Approaches In Quantum Field Theory, K D. Lamb, Christopher C. Gerry, Rainer Grobe

Faculty publications – Physics

We use a simplified essential state model to compare two quantum field theoretical approaches to study the creation of electron-positron pairs from the vacuum. In the unitary approach the system is characterized by a state with different numbers of particles that is described by occupation numbers and evolves with conserved norm. The nonunitary approach can predict the evolution of wave functions and density operators with a fixed number of particles but time-dependent norms. As an example to illustrate the differences between both approaches, we examine the degree of entanglement for the Klein paradox, which describes the creation of an electron-positron …

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Experimental Study Of Exclusive ²H(E,E'P)N Reaction Mechanisms At High Q², S. E. Kuhn, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, N. Kalantarians, A. Klein, M. R. Niroula, R. A. Niyazov, S. Tkachenko, L. B. Weinstein, J. Zhang, Et. Al., Clas Collaboration Jan 2007

Experimental Study Of Exclusive ²H(E,E'P)N Reaction Mechanisms At High Q², S. E. Kuhn, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, N. Kalantarians, A. Klein, M. R. Niroula, R. A. Niyazov, S. Tkachenko, L. B. Weinstein, J. Zhang, Et. Al., Clas Collaboration

Physics Faculty Publications

The reaction 2H(e,e(')p)n has been studied with full kinematic coverage for photon virtuality 1.75 < Q2< 5.5 GeV2. Comparisons of experimental data with theory indicate that for very low values of neutron recoil momentum (pn< 100 MeV/c) the neutron is primarily a spectator and the reaction can be described by the plane-wave impulse approximation. For 100 < pn< 750 MeV/c, proton-neutron rescattering dominates the cross section, while Delta production followed by the NΔ → NN transition is the primary contribution at higher momenta.

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Effects Of Molecular Motion On Deuteron Magic Angle Spinning Nmr Spectra, Yuanyuan Huang Jan 2007

Effects Of Molecular Motion On Deuteron Magic Angle Spinning Nmr Spectra, Yuanyuan Huang

Dissertations, Theses, and Masters Projects

Solid state deuteron NMR experiments, especially magic angle spinning (MAS) and off-magic angle spinning (OMAS), are developed to explore dynamical systems. A theoretical discussion of interactions relevant for spin-1 nuclei is presented. Practical aspects of MAS/OMAS experiments are described an detail. The dominant quadrupolar coupling interaction in deuteron NMR has been simulated and the effects of multiple-frame molecular motions on MAS/OMAS spectra are taken into account in this calculation. Effects of chemical shift anisotropy are also simulated, and shown to be small under conditions of rapid sample spinning.;Two numerical methods, direct integration and an efficient simulation routine based on Floquet …

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Quantifying Soil Chemical Properties Using Near Infrared Reflectance Spectroscopy, Robert L. Ficklin, Shane M. Foley, Robert E. Kissell Jr. Jan 2007

Quantifying Soil Chemical Properties Using Near Infrared Reflectance Spectroscopy, Robert L. Ficklin, Shane M. Foley, Robert E. Kissell Jr.

Journal of the Arkansas Academy of Science

Methodologies for determining soil chemical properties have evolved dramatically during the past century. Early geochemical analyses were conducted exclusively through the use of wet chemistry techniques that were relatively reliable but painstaking and subject to errors at various stages of analysis. Near infrared reflectance spectroscopy (NIRS) has emerged as a new approach for rapidly analyzing a variety of materials including soils. In this study soil samples were taken from eight study areas across the Ozark Highlands of Arkansas, and NIRS calibration models were developed to determine the accuracy of using NIRS to analyze soils compared with standard soil chemical analysis …

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Measurement And Modeling Of Light Transmission Through Turbid Media, Alois (Al) J. Adams, Michael Fahrenwald, Long Do Jan 2007

Measurement And Modeling Of Light Transmission Through Turbid Media, Alois (Al) J. Adams, Michael Fahrenwald, Long Do

Journal of the Arkansas Academy of Science

No abstract provided.

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Temperature-Driven Transition From The Wigner Crystal To The Bond-Charge-Density Wave In The Quasi-One-Dimensional Quarter-Filled Band, R. T. Clay, Rahul Hardikar, S. Mazumdar Jan 2007

Temperature-Driven Transition From The Wigner Crystal To The Bond-Charge-Density Wave In The Quasi-One-Dimensional Quarter-Filled Band, R. T. Clay, Rahul Hardikar, S. Mazumdar

Scholarship and Professional Work - LAS

It is known that within the interacting electron model Hamiltonian for the one-dimensional 1/4-filled band, the singlet ground state is a Wigner crystal only if the nearest-neighbor electron-electron repulsion is larger than a critical value. We show that this critical nearest-neighbor Coulomb interaction is different for each spin subspace, with the critical value decreasing with increasing spin. As a consequence, with the lowering of temperature, there can occur a transition from a Wigner crystal charge-ordered state to a spin-Peierls state that is a bond-charge-density wave with charge occupancies different from the Wigner crystal. This transition is possible because spin excitations …

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