Tracking Chirality Evolution in Tellurium Nanocrystals Via Polarization-Resolved Second-Harmonic Scattering.

Ji, Ruidong; Reuven, Bar; Kerrigan, Bradleigh; Markovich, Gil; Valev, Ventsislav K · Nano Lett · 2026

basic_science · Level V

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Abstract

Chirality pervades living systems and increasingly guides the design of functional nanomaterials. Yet weak or residual chirality can be difficult to detect, particularly in liquid-phase nanocrystal syntheses requiring noninvasive probes. Here we track chirality evolution in colloidal tellurium nanocrystals spanning strong, alloy-tuned, and reduced shape chirality. As morphological chirality decreases, linear circular dichroism drops by roughly an order of magnitude. In contrast, polarization-resolved second-harmonic scattering retains clear handedness-dependent responses. Across six independent observables─the nonlinear g-factor (g<sub>NL</sub>) and dual-circular polarization metrics (<i>DCP</i><sub>1</sub> and <i>DCP</i><sub>2</sub>) measured in forward and right-angled geometries─the signal reverses sign between enantiomorphs and remains well-resolved. The geometry dependence of these responses is consistent with interference between mirror symmetry-even and mirror symmetry-odd nonlinear tensor contributions. These results establish chiroptical second-harmonic scattering as a sensitive probe of weak structural asymmetry in nanocrystals exhibiting coupled shape and crystal chirality.