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M. B. Maple

Bio: M. B. Maple is an academic researcher from University of California, San Diego. The author has contributed to research in topics: Superconductivity & Magnetic susceptibility. The author has an hindex of 78, co-authored 953 publications receiving 26338 citations. Previous affiliations of M. B. Maple include Chiba University & Ohio State University.


Papers
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14 Dec 2007-Science
TL;DR: The electronic properties of a prototypical correlated insulator vanadium dioxide in which the metallic state can be induced by increasing temperature is reported, setting the stage for investigations of charge dynamics on the nanoscale in other inhomogeneous correlated electron systems.
Abstract: Electrons in correlated insulators are prevented from conducting by Coulomb repulsion between them. When an insulator-to-metal transition is induced in a correlated insulator by doping or heating, the resulting conducting state can be radically different from that characterized by free electrons in conventional metals. We report on the electronic properties of a prototypical correlated insulator vanadium dioxide in which the metallic state can be induced by increasing temperature. Scanning near-field infrared microscopy allows us to directly image nanoscale metallic puddles that appear at the onset of the insulator-to-metal transition. In combination with far-field infrared spectroscopy, the data reveal the Mott transition with divergent quasi-particle mass in the metallic puddles. The experimental approach used sets the stage for investigations of charge dynamics on the nanoscale in other inhomogeneous correlated electron systems.

1,283 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that superconductivity has been observed in the heavy fermion quasiparticles with an effective mass of approximately 50 µm/e.
Abstract: Superconductivity has been observed in ${\mathrm{PrOs}}_{4}{\mathrm{Sb}}_{12}$ at ${T}_{C}=1.85 \mathrm{K}$ and appears to involve heavy fermion quasiparticles with an effective mass ${m}^{*}\ensuremath{\sim}50 {m}_{e}$ as inferred from the jump in the specific heat at ${T}_{C},$ the upper critical field near ${T}_{C},$ and the normal state electronic specific heat. Thermodynamic and transport measurements suggest that the heavy fermion state has a quadrupolar origin, although a magnetic origin cannot be completely ruled out.

589 citations

Journal ArticleDOI
TL;DR: Muon-spin-relaxation and bulk measurements of the magnetic-field penetration depth suggest that the cuprate high-{ital T}{sub {ital c}}, bismuthate, organic Chevrel-phase, and heavy-fermion systems possibly belong to a unique group of superconductors characterized by high transition temperatures.
Abstract: Muon-spin-relaxation and bulk measurements of the magnetic-field penetration depth suggest that the cuprate high-${\mathit{T}}_{\mathit{c}}$, bismuthate, organic Chevrel-phase, and heavy-fermion systems possibly belong to a unique group of superconductors characterized by high transition temperatures ${\mathit{T}}_{\mathit{c}}$ relative to the values of ${\mathit{n}}_{\mathit{s}}$/${\mathit{m}}^{\mathrm{*}}$ (carrier density/effective mass). This feature distinguishes these exotic superconductors from ordinary BCS superconductors.

559 citations

Journal ArticleDOI
TL;DR: Transport, thermal, and magnetic data for the heavy electron system URu2Si2 indicate that a charge- or spin-density-wave transition opens an energy gap over a portion of the Fermi surface below T0roughly-equal17.5 K and demonstrate that bulk superconductivity occurs below T/sub c/roughly
Abstract: Transport, thermal, and magnetic data for the heavy electron system ${\mathrm{URu}}_{2}$${\mathrm{Si}}_{2}$ indicate that a charge- or spin-density-wave transition opens an energy gap of \ensuremath{\sim}11 meV over a portion of the Fermi surface below ${\mathrm{T}}_{0}$\ensuremath{\approxeq}17.5 K and demonstrate that bulk superconductivity occurs below ${\mathrm{T}}_{\mathrm{c}}$\ensuremath{\approxeq}1.5 K. The pressure dependences of ${\mathrm{T}}_{0}$ and ${\mathrm{T}}_{\mathrm{c}}$ support this interpretation. The unusually large initial slope of the upper critical magnetic field (9.2 T/K) is consistent with the high values of the electronic-specific-heat coefficient and the electrical resistivity.

501 citations

Journal ArticleDOI
29 Oct 1998-Nature
TL;DR: In this paper, the authors reported the observation of local modes in La-filled skutterdite antimonides, using heat capacity, elastic constant and inelastic neutron scattering measurements.
Abstract: Filled skutterudite antimonides1,2 are cubic compounds with the formula RM4Sb12, where R is a rare-earth element (such as La or Ce), and M is a transition metal (for example, Fe or Co). The rare-earth ion is weakly bound in an oversized atomic cage formed by the other atoms. Its presence has been shown to cause a dramatic reduction in the lattice component of the thermal conductivity, while having little effect on the electronic properties3,4,5 of the compound. This combination of properties makes filled skutterudites of interest as thermoelectric materials. It has been suggested4 that localized, incoherent vibrations of the rare-earth ion are responsible for the reduction in thermal conductivity, but no direct evidence for these local vibrational modes exists. Here we report the observation of local modes in La-filled skutterudites, using heat capacity, elastic constant and inelastic neutron scattering measurements. The La atoms show unusual thermodynamic behaviour, characterized by the presence of two low-energy localized modes. Our results suggest that consideration of local modes will play an important role in the design of the next generation of thermoelectric materials.

473 citations


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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: In this paper, the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations, are discussed.
Abstract: This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.

20,824 citations

Journal ArticleDOI
10 Mar 1970

8,159 citations

Journal ArticleDOI
TL;DR: The dynamical mean field theory of strongly correlated electron systems is based on a mapping of lattice models onto quantum impurity models subject to a self-consistency condition.
Abstract: We review the dynamical mean-field theory of strongly correlated electron systems which is based on a mapping of lattice models onto quantum impurity models subject to a self-consistency condition. This mapping is exact for models of correlated electrons in the limit of large lattice coordination (or infinite spatial dimensions). It extends the standard mean-field construction from classical statistical mechanics to quantum problems. We discuss the physical ideas underlying this theory and its mathematical derivation. Various analytic and numerical techniques that have been developed recently in order to analyze and solve the dynamical mean-field equations are reviewed and compared to each other. The method can be used for the determination of phase diagrams (by comparing the stability of various types of long-range order), and the calculation of thermodynamic properties, one-particle Green's functions, and response functions. We review in detail the recent progress in understanding the Hubbard model and the Mott metal-insulator transition within this approach, including some comparison to experiments on three-dimensional transition-metal oxides. We present an overview of the rapidly developing field of applications of this method to other systems. The present limitations of the approach, and possible extensions of the formalism are finally discussed. Computer programs for the numerical implementation of this method are also provided with this article.

5,230 citations