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Full-Text Articles in Physical Sciences and Mathematics
Linked-Cluster Expansion For The Green's Function Of The Infinite-U Hubbard Model, Ehsan Khatami, Edward Perepelitsky, Marcos Rigol, Sriram B. Shastry
Linked-Cluster Expansion For The Green's Function Of The Infinite-U Hubbard Model, Ehsan Khatami, Edward Perepelitsky, Marcos Rigol, Sriram B. Shastry
Ehsan Khatami
We implement a highly efficient strong-coupling expansion for the Green's function of the Hubbard model. In the limit of extreme correlations, where the onsite interaction is infinite, the evaluation of diagrams simplifies dramatically enabling us to carry out the expansion to the eighth order in powers of the hopping amplitude. We compute the finite-temperature Green's function analytically in the momentum and Matsubara frequency space as a function of the electron density. Employing Padé approximations, we study the equation of state, Kelvin thermopower, momentum distribution function, quasiparticle fraction, and quasiparticle lifetime of the system at temperatures lower than, or of the …
Magnetic Correlations And Pairing In The 1/5-Depleted Square Lattice Hubbard Model, Ehsan Khatami, Rajiv R.P. Singh, Warren E. Pickett, Richard T. Scalettar
Magnetic Correlations And Pairing In The 1/5-Depleted Square Lattice Hubbard Model, Ehsan Khatami, Rajiv R.P. Singh, Warren E. Pickett, Richard T. Scalettar
Ehsan Khatami
We study the single-orbital Hubbard model on the 1/5-depleted square-lattice geometry, which arises in such diverse systems as the spin-gap magnetic insulator CaV4O9 and ordered-vacancy iron selenides, presenting new issues regarding the origin of both magnetic ordering and superconductivity in these materials. We find a rich phase diagram that includes a plaquette singlet phase, a dimer singlet phase, a Néel and a block-spin antiferromagnetic phase, and stripe phases. Quantum Monte Carlo simulations show that the dominant pairing correlations at half filling change character from d wave in the plaquette phase to extended s wave upon transition to the Néel phase. …
Finite-Temperature Properties Of Strongly Correlated Fermions In The Honeycomb Lattice, Baoming Tang, Thereza Paiva, Ehsan Khatami, Marchos Rigol
Finite-Temperature Properties Of Strongly Correlated Fermions In The Honeycomb Lattice, Baoming Tang, Thereza Paiva, Ehsan Khatami, Marchos Rigol
Ehsan Khatami
We study finite-temperature properties of strongly interacting fermions in the honeycomb lattice using numerical linked-cluster expansions and determinantal quantum Monte Carlo simulations. We analyze a number of thermodynamic quantities, including the entropy, the specific heat, uniform and staggered spin susceptibilities, short-range spin correlations, and the double occupancy at and away from half filling. We examine the viability of adiabatic cooling by increasing the interaction strength for homogeneous as well as for trapped systems. For the homogeneous case, this process is found to be more efficient at finite doping than at half filling. That, in turn, leads to an efficient adiabatic …
Fluctuation-Dissipation Theorem In An Isolated System Of Quantum Dipolar Bosons After A Quench, Ehsan Khatami, Guido Pupillo, Mark Srednicki, Marcos Rigol
Fluctuation-Dissipation Theorem In An Isolated System Of Quantum Dipolar Bosons After A Quench, Ehsan Khatami, Guido Pupillo, Mark Srednicki, Marcos Rigol
Ehsan Khatami
We examine the validity of fluctuation-dissipation relations in isolated quantum systems taken out of equilibrium by a sudden quench. We focus on the dynamics of trapped hard-core bosons in one-dimensional lattices with dipolar interactions whose strength is changed during the quench. We find indications that fluctuation-dissipation relations hold if the system is nonintegrable after the quench, as well as if it is integrable after the quench if the initial state is an equilibrium state of a nonintegrable Hamiltonian. On the other hand, we find indications that they fail if the system is integrable both before and after quenching.
Trends In The Ams Education Symposium And Highlights From 2012, Rajul Pandya, Donna Charlevoix, Eugene Cordero, David Smith, Sepi Yalda
Trends In The Ams Education Symposium And Highlights From 2012, Rajul Pandya, Donna Charlevoix, Eugene Cordero, David Smith, Sepi Yalda
Eugene C. Cordero
The Department of Meteorology (now Atmospheric Sciences) at the University of Utah faced reductions in state funding in 2008 that reduced support for nontenured instructors at the same time that the faculty were becoming increasingly successful obtaining federally supported research grants. A faculty retreat and subsequent discussions led to substantive curriculum changes to modernize the curriculum, enhance course offerings for undergraduate and graduate students, and improve the overall efficiency of the academic program. Maintaining discipline standards and existing teaching loads were important constraints on these changes. Key features of the curriculum revisions for undergraduate majors included eliminating a very rigid …
Reproduction Of Twentieth Century Intradecadal To Multidecadal Surface Temperature Variability In Radiatively Forced Coupled Climate Models, Patrick T. Brown, Eugene C. Cordero, Steven A. Mauget
Reproduction Of Twentieth Century Intradecadal To Multidecadal Surface Temperature Variability In Radiatively Forced Coupled Climate Models, Patrick T. Brown, Eugene C. Cordero, Steven A. Mauget
Eugene C. Cordero
[1] Coupled Model Intercomparison Project 3 simulations that included time-varying radiative forcings were ranked according to their ability to consistently reproduce twentieth century intradecadal to multidecadal (IMD) surface temperature variability at the 5° by 5° spatial scale. IMD variability was identified using the running Mann-Whitney Z method. Model rankings were given context by comparing the IMD variability in preindustrial control runs to observations and by contrasting the IMD variability among the ensemble members within each model. These experiments confirmed that the inclusion of time-varying external forcings brought simulations into closer agreement with observations. Additionally, they illustrated that the magnitude of …
Chemical Activity In Yba2cu3o7 − Δ Across The Normal To Superconducting Phase Transition, Juana Vivó Acrivos
Chemical Activity In Yba2cu3o7 − Δ Across The Normal To Superconducting Phase Transition, Juana Vivó Acrivos
Juana Vivó Acrivos
The Gibbs free enthalpy, chemical activity across the transition temperature to superconductivity, Tc in YBa2Cu3O7 − δ is obtained from reciprocally enhanced X-Ray absorbance, XAS and diffraction, XRD data near the Ba L3,2 edges' energy Ea, and orientations in the X-ray beam for preferred Miller indexed [HKL] planes' scattering, that are enhanced near Tc. The standard enthalpy and entropy for the formation of mixed normal metal/superconducting domains above Tc, determined individually across the two Ba L3,2 edges, to better than a percent accuracy: ΔH≠≥ = − 220 meV, and ΔS≠≥ = − 2 meV/K when 121 ≥ T ≥ 92 …
The Investigation Of Epr Paramagnetic Probe Line Width And Shape Temperature Dependence In High-Temperature Superconductors Of Bi–Pb–Sr–Ca–Cu–O System, J. G. Chigvinadze, Juana Vivó Acrivos, I. G. Akhvlediani, M. I. Chubabria, T. L. Kalabegishvili, T. I. Sanadze
The Investigation Of Epr Paramagnetic Probe Line Width And Shape Temperature Dependence In High-Temperature Superconductors Of Bi–Pb–Sr–Ca–Cu–O System, J. G. Chigvinadze, Juana Vivó Acrivos, I. G. Akhvlediani, M. I. Chubabria, T. L. Kalabegishvili, T. I. Sanadze
Juana Vivó Acrivos
The work is related with the finding out of magnetic phases in strongly anisotropic high-temperature superconductor Bi1,7Pb0,3Sr2Ca2Cu3O10-δ in the temperature region where the superconductor is in the normal state. It was studied the temperature dependence of the paramagnetic probe EPR line width. In the normal state at T>Tc near 175 K it was revealed a pick in the temperature dependence of line width. In this region it was observed the time increase of the line width with the characteristic time ~ 17 min. This shows the possibility of magnetic phase formation in this material.
An Ozone-Modified Refractive Index For Vertically Propagating Planetary Waves, Terrence R. Nathan, Eugene C. Cordero
An Ozone-Modified Refractive Index For Vertically Propagating Planetary Waves, Terrence R. Nathan, Eugene C. Cordero
Eugene C. Cordero
[1] An ozone-modified refractive index (OMRI) is derived for vertically propagating planetary waves using a mechanistic model that couples quasigeostrophic potential vorticity and ozone volume mixing ratio. The OMRI clarifies how wave-induced heating due to ozone photochemistry, ozone transport, and Newtonian cooling (NC) combine to affect wave propagation, attenuation, and drag on the zonal mean flow. In the photochemically controlled upper stratosphere, the wave-induced ozone heating (OH) always augments the NC, whereas in the dynamically controlled lower stratosphere, the wave-induced OH may augment or reduce the NC depending on the detailed nature of the wave vertical structure and zonal mean …
Yba2cu3o7 Electro-Magneto-Optic Effects In Ba L2,3 X-Ray Absorption Near Tc, Juana Vivó Acrivos
Yba2cu3o7 Electro-Magneto-Optic Effects In Ba L2,3 X-Ray Absorption Near Tc, Juana Vivó Acrivos
Juana Vivó Acrivos
The onset of electro magneto-optic effects, observed at the Ba L2,3 edges synchrotron X-ray absorption by a YBa2Cu3O7 single crystal, 10 K above the transition temperature to superconductivity, Tc ~ 92 K is used to identify the role played by the Ba donor layer in the transition to superconductivity in the CuO2 layers. Negative permeability leads to Faraday rotation of the transmitted beam below T = 112 to 56 K for the 22 μm thick single crystal (c-axis orientation of 8π/18 relative to εX-rays) and sharp changes in the density of empty final states lead to zero transmitted radiation in …
Transport Out Of The Antarctic Polar Vortex From A Three-Dimensional Transport Model, Shuhua Li, Eugene Cordero, David J. Karoly
Transport Out Of The Antarctic Polar Vortex From A Three-Dimensional Transport Model, Shuhua Li, Eugene Cordero, David J. Karoly
Eugene C. Cordero
[1] A three-dimensional chemical transport model is utilized to study the transport out of the Antarctic polar vortex during the southern hemisphere spring. On average, over five consecutive years between 1993 and 1997, horizontal transport out of the vortex into the midlatitude stratosphere is smaller than vertical transport into the troposphere. However, there is significant interannual variability in the magnitude of mass exchange, which is related to year-to-year fluctuations in planetary wave activity. In 1994 the net loss of the vortex tracer mass in September is similar to that in October. However, the relative mass flux entering the midlatitude stratosphere …
Decomposition Of Pascal’S Kernels Mod PS, Richard P. Kubelka
Decomposition Of Pascal’S Kernels Mod PS, Richard P. Kubelka
Richard P. Kubelka
For a prime p we define Pascal's Kernel K(p,s) = [k(p,s)ij]∞i,j=0 as the infinite matrix satisfying k(p,s)ij = 1/px(i+jj) mod p if (i+jj) is divisible by ps and k(p,s)ij = 0 otherwise. While the individual entries of Pascal's Kernel can be computed using a formula of Kazandzidis that has been known for some time, our purpose here will be to use that formula to explain the global geometric patterns that occur in K(p,s). Indeed, if we consider the finite (truncated) versions of K(p,s), we find that they can be decomposed into superpositions of tensor products of certain primitive p x …
Chemical Analysis By X-Ray Spectroscopy Near Phase Transitions In The Solid State, Juana Vivó Acrivos, L. Nguyen, T. Norman, C. T. Lin, W. Y. Liang, J. M. Honig, P Somasundaran
Chemical Analysis By X-Ray Spectroscopy Near Phase Transitions In The Solid State, Juana Vivó Acrivos, L. Nguyen, T. Norman, C. T. Lin, W. Y. Liang, J. M. Honig, P Somasundaran
Juana Vivó Acrivos
The methods discussed in this work show that the types of changes which may be observed, by precise XAS measurements of Absorbance A versus temperature, across a phase transition are: the changes in the relaxation time of the final states due to fluctuations near a phase transition; the detection of the anomalous Bragg condition coupled to phonon modes XAS enhancement that identifies the temperature interval where the phonon modes are active, the symmetry changes which introduce new allowed transitions to finite states below an element edge, near Tc indicate what symmetry changes occur, and the method of XTDAFST0 = …
Spin-Exchange Term In The Solvent Equation Of State Near The Critical Point For Electron Transfer Reactions, Juana Vivó Acrivos
Spin-Exchange Term In The Solvent Equation Of State Near The Critical Point For Electron Transfer Reactions, Juana Vivó Acrivos
Juana Vivó Acrivos
Phenomenological Equations of State (EOS) for fluids near their critical point have been obtained using literature compression factor data, Zc = Pc Vc/(n R Tc) = 0.40 to 0.10 in Table I (Pc, Vc/n, Tc are the pressure, volume per n mole, and the absolute temperature of the fluid at the critical point). The objective is to explain the deviations from the van der Waals value, Zc(vdW) = 3/8 (-70 % for molten Se and alkali metals up to 6 % for molten Pb, Hg, and In) by including in the commonly used phenomenological thermodynamic relations a term which explicitly …
Solid State Phase Transitions Characterized By Esr And Xas, Juana Vivó Acrivos
Solid State Phase Transitions Characterized By Esr And Xas, Juana Vivó Acrivos
Juana Vivó Acrivos
Measurements of the relaxation time, of electron systems to a disturbance, by two different spectroscopic methods are examined in detail, with the purpose to establish how the presence of fluctuations near a solid state phase transition are made evident in insulators, conductors and superconductors. The absolute temperature and the relaxation time determine the thermodynamic stability of the electronic system near a phase transition by the Uncertainty Principle. At a given temperature T, Landau and Lifshitz obtain the stability from the lower limit of the uncertainty in entropy in units of the Boltzmann constant, S/kB << 1 when T >> 3.82 K ps. Magnetic resonance …
Student Evaluations Of Teaching Effectiveness: The Interpretation Of Observational Data And The Principle Of Faute De Mieux, B. Burt Gerstman
Student Evaluations Of Teaching Effectiveness: The Interpretation Of Observational Data And The Principle Of Faute De Mieux, B. Burt Gerstman
B. Burt Gerstman
Student opinion surveys are important but widely misunderstood tools for evaluating teaching effectiveness. In this brief review, an analogy is drawn between the use and interpretation of observational data for public health and biomedical research and the use of student opinion data in evaluating teach ing effectiveness. Sources of systematic error in the form of selection bias, information bias, and confounding are defined and illustrated. Original data concerning intermittent "quid pro quo" confounding (i.e., the effect of expected grades on student evaluations of teaching) are presented. Finally, the principle of faute de mieux ("lack of anything better") and the interpretation …
Ozone Heating And The Destabilization Of Traveling Waves During Summer, Terrence R. Nathan, Eugene Cordero, Long Li
Ozone Heating And The Destabilization Of Traveling Waves During Summer, Terrence R. Nathan, Eugene Cordero, Long Li
Eugene C. Cordero
The effects of ozone heating on the linear stability of lower stratospheric traveling waves of the summertime, extratropical circulation are examined. Based on coupled equations for the quasigeostrophic potential vorticity and ozone volume mixing ratio, it is shown that the diabatic heating arising from ozone advection can offset the damping due to Newtonian cooling, leading to wave amplification and significant changes in the structure and zonally rectified fluxes of the wave fields in both the lower stratosphere and troposphere. The vertical profile of the zonal mean wind plays a crucial role in determining whether the ozone heating destabilizes eastward and/or …
Dynamic Phenomena In Superconducting Oxides By Esr, Juana Vivó Acrivos, Lei Chen, C. M. Burch, P. Metcalf, J. M. Honig, R. S. Liu, K. K. Singh
Dynamic Phenomena In Superconducting Oxides By Esr, Juana Vivó Acrivos, Lei Chen, C. M. Burch, P. Metcalf, J. M. Honig, R. S. Liu, K. K. Singh
Juana Vivó Acrivos
Dynamic electron spin resonance (ESR) measurements compare the paramagnetic and antiferromagnetic (AF) properties of superconducting oxides in the range 4 K to room temperature, at 8 MHz and 9.36 GHz. Two are derivatives of YBa2Cu30 7: 1: Nd(Nd0.05Ba0.95 )2Cu30 7, Te0 =72 K and II: Y0.2Cao.8Sr2[Cu2(Tlo.5Pb0.5 )]07, Te0 =108 K and two are cases where AF ordering dominates the weak superconductivity: III: Nb01.1> 1. 25 ~Teo~ 10 K and IV: La2Ni04.00, 70 K :::: Teo:::: 40 K. At temperatures 298:::: T:::: 64 K, the ESR absorption by I indicates orthorhombic symmetry. The peaks at Ke =2.06, gb =2.13, and Ka …
Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser
Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser
June Ann Oberdorfer
No abstract provided.
Esr Study Of Optically Induced Phase Transitions, Juana Vivó Acrivos, H. P. Hughes, S. S.P. Parkin
Esr Study Of Optically Induced Phase Transitions, Juana Vivó Acrivos, H. P. Hughes, S. S.P. Parkin
Juana Vivó Acrivos
We have identified an optically enhanced magnetic phase transition in the newly synthesized organic molecular charge transfer salt, (BEDT-TTF)3Ta2F11 (BEDT-TTF bisethylenedithiolotetrathiafulvalene) by ESR absorption measurements in the X band microwave region. At room temperature, only a doublet state ESR absorption is observed, but below 30 K severa~ tripl~t E.SR absorpti_ons appear. The orientation dependence of the ESR absorption under lllummat10n at energies near the band gaps in the material ( 640 nm, T = 12 to 5 K H0 < 0.34 T) indicates that there are rapid spin exchange processes with times r < w-s; near 7 ~o 5 K.along cert~in ~rystallographic directions with a temperature dependen~e suggesting spm-lattlce relaxation times which proceed via Van Vleck "direct processes." This, to our knowledge, is the first case where the magnetic properties of a charge transfer salt are altered by the interaction with photons of energy equal to the band gaps in a low dimensional solid providing a new, interesting way to investigate these materials.
Uses And Abuses Of Wastewater Injection Wells In Hawaii, F. L. Peterson, June Ann Oberdorfer
Uses And Abuses Of Wastewater Injection Wells In Hawaii, F. L. Peterson, June Ann Oberdorfer
June Ann Oberdorfer
During the past two decades in Hawaii, more than 500 injection wells for the disposal of domestic sewage wastewater have been constructed and operated. Thus far, contamination of potable groundwater supplies has not been a problem. Many of the injection wells, however, have not performed as designed, and aquifer clogging and reduced injection capacity have produced numerous well failures resulting in public health, legal, and financial problems. Factors most commonly responsible for the well problems have been unfavorable hydrogeology, underdesign of injection well capacity, poor effluent quality, and lack of injection well maintenance. Detailed study of clogging mechanisms in the …
Nmr Measurements On Intercalated 3r-Tas2.Ix (I=Nh3 And N2h4), N. H. Handly, Juana Vivó Acrivos
Nmr Measurements On Intercalated 3r-Tas2.Ix (I=Nh3 And N2h4), N. H. Handly, Juana Vivó Acrivos
Juana Vivó Acrivos
No abstract provided.
Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Vivó Acrivos, S.S. P. Parkin
Xanes In (Tmtsef)2re04: Polarization Dependence Of The Se K-Edge, Juana Vivó Acrivos, S.S. P. Parkin
Juana Vivó Acrivos
We have measured XANES (X-ray Absorption Near Edge Spectra) near the Re Li (i=l,II,III) edges in (TMTTF)2Re04 and (TMTSeF) 2Re04 and the Se K edge in the latter compound. An important dependence of the XANES at the Se K edge on the polarisation of the incident beam with respect to the crystal axes was observed, whose interpretation can give information on the symmetry of the unoccupied conduction band states. The positions of the Re L edges were compared with those in several inorganic compounds containing Re in various oxidation states, and were found to be, within experimental error, the same …
Sources Of Nosocomial Infections In Immunocompromised Patients (Letter), B. Burt Gerstman
Sources Of Nosocomial Infections In Immunocompromised Patients (Letter), B. Burt Gerstman
B. Burt Gerstman
No abstract provided.
Measurement Of Synchrotron X-Ray Energies And Line Shapes Using Diffraction Markers, Juana Vivó Acrivos, S.S. P. Parkin, K. Hathaway, J. R. Reynolds, M. P. Klein, A. Thompson, D. Goodin
Measurement Of Synchrotron X-Ray Energies And Line Shapes Using Diffraction Markers, Juana Vivó Acrivos, S.S. P. Parkin, K. Hathaway, J. R. Reynolds, M. P. Klein, A. Thompson, D. Goodin
Juana Vivó Acrivos
Standard reference markers for accurate, reproducible synchrotron x-ray energies are obtained using a three Si crystal spectrometer. The first two crystals are in the monochromator and the third is used to obtain diffraction markers which monitor the energy. Then for any value of the glancing angle on the reference Si crystal the energy for the (333) diffraction must occur at 3/4 that of the (444) and 3/5 of that for the (555). This establishes for the first time an absolute synchrotron energy scale. Higher-order diffractions are used to determine excitation line profiles. We conclude that the use of reference diffractions …
Conduction Band Symmetry In Ta Chalcogenides From Ta L Edge X-Ray Absorption Spectroscopy (Xas), Juana Vivó Acrivos, S.S. P. Parkin, J. Code, J. Reynolds, K. Hathaway, H. Kurasaki, E. Marseglia
Conduction Band Symmetry In Ta Chalcogenides From Ta L Edge X-Ray Absorption Spectroscopy (Xas), Juana Vivó Acrivos, S.S. P. Parkin, J. Code, J. Reynolds, K. Hathaway, H. Kurasaki, E. Marseglia
Juana Vivó Acrivos
No abstract provided.
Effects Of N2h4 On The Transition Temperature In The Anisotropic Superconductor Tase3, K. Yamaya, T. H. Geballe, Juana Vivó Acrivos, J. Code
Effects Of N2h4 On The Transition Temperature In The Anisotropic Superconductor Tase3, K. Yamaya, T. H. Geballe, Juana Vivó Acrivos, J. Code
Juana Vivó Acrivos
No abstract provided.
Mott G-Ratios In Rbx(Nh3)1-X And Oxidation State Of Rubidium Compounds From Xas, Juana Vivó Acrivos, K. Hathaway, A. Robertson, M. P. Klein, A. Thompson
Mott G-Ratios In Rbx(Nh3)1-X And Oxidation State Of Rubidium Compounds From Xas, Juana Vivó Acrivos, K. Hathaway, A. Robertson, M. P. Klein, A. Thompson
Juana Vivó Acrivos
The x-ray absorption spectra (XAS) of Rb metal, Rh,("JH,J, ,, 2H-NbSe2Rb111x and RbBr near the Rb K-edge have been used to ascertain that the oxidation state V of rubidium dissolved in ammonia and intt:rcalated in the layer compound is in the range 0 < V < I. Theobservededge shifts with temperature for semimctals are explainedin terms of the population of band states, and the ratio of the density states near the mobility edge over that calculated for a free electron model, i.e. the Mott ratio g, is ascertained using a semiempirical relation developed for the x-ray absorbance from Is levels to empty states ncar the mobility edge.
Properties Of Hxtas2, D. W. Murphy, F. J. Disalvo, G. W. Hull, J. V. Waszczak, S. F. Meyers, G. R. Stewart, S. Early, Juana Vivó Acrivos, T. H. Geballe
Properties Of Hxtas2, D. W. Murphy, F. J. Disalvo, G. W. Hull, J. V. Waszczak, S. F. Meyers, G. R. Stewart, S. Early, Juana Vivó Acrivos, T. H. Geballe
Juana Vivó Acrivos
The preparation of Hx TaS2 (0 < x < 0.87) is described. The compounds are only marginally stable at room temperature, slowly evolving H2S and H2 (and possibly Hp in air). Magnetic susceptibility data show that a low temperature transformation in 2H ... TaS2 (at so•K) is suppressed with the addition of hydrogen, and· at the same time the superconducting transition temperature T c rises from 0.8 to ~4.2•K at x = 0.11. Heat capacity measurements near this concentration show the superconductivity to be a bulk effect. Finally, by correlation of this data with susceptibility and T c measurements in other intercalation compounds, we suggest that the rise of T c (at low electron transfer) is due to suppression of the low temperature transformation and not due to an excitonic mechanism of superconductivity.
Properties Of Intercalated 2h-Nbse2, 4hb-Tas2 And 1t-Tas2, S. F. Meyer, R. E. Howard, G. R. Stewart, Juana Vivó Acrivos, T. H. Geballe
Properties Of Intercalated 2h-Nbse2, 4hb-Tas2 And 1t-Tas2, S. F. Meyer, R. E. Howard, G. R. Stewart, Juana Vivó Acrivos, T. H. Geballe
Juana Vivó Acrivos
The layered compounds 2H-NbSe, 24Hb-TaS, 2and 1T-TaS2 have been intercalated with organic molecules; and the resulting crystal structure, heat capacity, conductivity, and superconductivity have been studied. The coordination in the disulfide layers was found to be unchanged in the product phase. Resistance minima appear and the superconducting transition temperature is reduced in the NbSe2 complex. Conversely, superconductivity is induced in the 4Hb-TaS2 complex. Corresponding evidence of a large change of the density of states, negative for 2H-NbSe2 and positive for 4Hb-TaS2, was also observed upon intercalation. The transport properties of all the intercalation complexes show a pronounced dependence upon the …