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Light-Matter interactions in topological semimetals: novel physics to devices (Conference Presentation)
Author(s): Ritesh Agarwal
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Paper Abstract

We will also discuss our efforts to explore the optoelectronic properties of MoxW1-xTe2, which are type-II Weyl semimetals, i.e., gapless topological states of matter with broken inversion and/or time reversal symmetry, which exhibit unconventional responses to externally applied fields. We have observed spatially dispersive circular photogalvanic effect (s-CPGE) over a wide spectral range from mid-IR to visible region in these materials. This effect shows exclusively in the Weyl phase and vanishes upon temperature induced topological phase change. Since the photon energy in our experiments leads to interband transitions between different electronic bands, we use the density matrix formalism to describe the photocurrent response under chiral optical excitation and obtain microscopic insights into the observed phenomena. We will discuss how spatially inhomogeneous optical excitation and unique symmetry and band structure of Weyl semimetals produces CPGE in these systems. Implications for studying band topologies in these class of materials via photogalvanic effects will also be discussed. These results provide a new approach to controlling photoresponse by patterning optical fields in certain class of broken-symmetry materials to store, manipulate and transmit information over a wide spectral range.

Paper Details

Date Published: 8 March 2019
Proc. SPIE 10927, Photonic and Phononic Properties of Engineered Nanostructures IX, 109271D (8 March 2019); doi: 10.1117/12.2517171
Show Author Affiliations
Ritesh Agarwal, Univ. of Pennsylvania (United States)

Published in SPIE Proceedings Vol. 10927:
Photonic and Phononic Properties of Engineered Nanostructures IX
Ali Adibi; Shawn-Yu Lin; Axel Scherer, Editor(s)

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