Author: Srini Krishnamurthy
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Thermal insulator transition induced by interface scattering
We develop an effective medium model of thermal conductivity that accounts for both percolation and interface scattering.
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Experimental Demonstration of a Broadband All-Dielectric Metamaterial Perfect Reflector
Here we present the demonstration of a single-negative all-dielectric metamaterial that possesses peak reflectance over 99% and an average reflectance over 98% across a 200 nm wide bandwidth in the short-wavelength infrared region.
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Fabrication of Highly Spin-Polarized Co2FeAl0.5Si0.5 Thin-Films
Ferromagnetic Heusler Co2FeAl0.5Si0.5 epitaxial thin-films have been fabricated in the L21 structure with saturation magnetizations over 1200 emu/cm3.
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Generalized Effective-Medium Theory for Metamaterials
We present an effective-medium model for calculating the frequency-dependent effective permittivity ε(ω) and permeability μ(ω) of metamaterial composites containing spherical particles with arbitrary permittivity and permeability.
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Perfect Dielectric-Metamaterial Reflector
We exploit the Mie resonance in dielectric microparticles to design a single-negative metamaterial monolayer with near-unity reflectivity and negligible absorptivity.
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Temperature- and Wavelength-dependent Two-photon and Free-carrier Absorption in GaAs, InP, GaInAs, and InAsP
We present full-band structure calculations of temperature- and wavelength-dependent two-photon absorption coefficients and free-carrier absorption cross sections in GaAs, InP, and 0.92 eV-band gap Ga64In36As and InP60As40 alloys.
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Transfer Lengths and Spin Injection from a Three-Dimensional Ferromagnet Into Graphene
Here we develop a unified theory to understand the observed spin-injection signals and their dependence on a dc-bias current in these devices by different groups.
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Large Magnetoresistance of Thick Polymer Devices Having La0.67 Sr0.33 MnO3 Electrodes
We report magnetoresistance(MR) measurements for structures with micrometer-thick regioregular, polythiophene (rr-P3HT) polymer layers between two ferromagnetic contacts.
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Temperature Dependent Nonlinear Absorption in InSb
Temperature dependent two-photon and free-carrier absorption spectra of InSb are measured using femtosecond, picosecond, and nanosecond IR sources. Measurements over this substantial range of pulsewidths give results consistent with a recent theoretical model.
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Spectral and Temperature Dependence of Nonlinear Absorption in InSb
Temperature dependent two-photon and free-carrier absorption spectra of InSb are measured using a tunable picosecond source via temperature controlled Z-scan experiments and show good agreement with theoretical predictions.