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Fractal Lévy Heat Transport in Nanoparticle Embedded Semiconductor Alloys
journal contribution
posted on 2015-07-08, 00:00 authored by Amr M. S. Mohammed, Yee Rui Koh, Bjorn Vermeersch, Hong Lu, Peter G. Burke, Arthur C. Gossard, Ali ShakouriMaterials with embedded nanoparticles
are of considerable interest for thermoelectric applications. Here,
we experimentally characterize the effect of nanoparticles on the
recently discovered Lévy phonon transport in semiconductor
alloys. The fractal space dimension α ≈ 1.55 of quasiballistic
(superdiffusive) heat conduction in (ErAs)x:InGaAlAs is virtually independent of the Er content 0.001 < x < 0.1 but instead controlled by alloy scattering of
the host matrix. The increased nanoparticle concentration does reduce
the diffusive recovery length by an order of magnitude. The bulk conductivity
drops by 3-fold, in close agreement with a Callaway model. Our results
may provide helpful hints toward engineering superdiffusive heat
transport similar to what has been achieved with light in Lévy
glasses.