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Giant photoinduced chirality in thin film Ge2Sb2Te5

DOI: 10.1002/pssr.201900449 DOI Help

Authors: Janaki Shanmugam (University of Oxford) , Konstantin B. Borisenko (University of Oxford) , Andrew Luers (University of Oxford) , Paul Ewart (University of Oxford) , Priyav Shah (University of Oxford) , Benjamin A. O. Williams (University of Oxford) , Christopher Craig (University of Southampton) , Daniel W. Hewak (University of Southampton) , Rohanah Hussain (Diamond Light Source) , Tamas Javorfi (Diamond Light Source) , Giuliano Siligardi (Diamond Light Source) , Michel Bosman (Technology and Research (A*STAR); National University of Singapore) , Angus I. Kirkland (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physica Status Solidi (rrl) – Rapid Research Letters , VOL 1

State: Published (Approved)
Published: October 2019
Diamond Proposal Number(s): 9375 , 15028

Abstract: Induction, tuning, or amplification of chirality in various classes of materials and probing their chiral response are subjects of growing research. Herein, a large chiral signal that is rapidly imprinted in achiral amorphous Ge2Sb2Te5 (GST) thin films measured using synchrotron circular dichroism spectroscopy is reported. The chirality is induced by illuminating the films with pulsed circularly polarized (chiral) laser light for less than 2 μs in total. The effects of laser fluence and film thickness on the chiral response are described. The correlation of the optical results with structural studies by electron diffraction and model simulations suggests that alignment of reamorphized fragments in the crystallized film along the electric field vector of the light forms the centers that are responsible for the observed chirality. These results suggest opportunities for practical applications of this phenomenon and provide avenues for further studies of chirality induction in materials with impact in a wide range of disciplines.

Journal Keywords: chalcogenide films; circular dichroism; laser-induced transformations; photoinduced chirality; reduced density function analysis

Subject Areas: Materials

Instruments: B23-Circular Dichroism