Investigation of the nonlinear optical frequency conversion in ultrathin franckeite heterostructures

Author(s)

Cadore, Alisson R. ; Ore, Alexandre S. M. V. ; Steinberg, David ; Zapata, Juan D. ; de Souza, Eunezio A. T. ; Bahamon, Dario A. ; de Matos, Christiano J. S.

• Document type: Journal article
• Source: Journal of Applied Physics; v. 135, n. 8, p. 10-pg., 2024-02-28.

Abstract

Layered franckeite is a natural superlattice composed of two alternating layers of different compositions, SnS2- and PbS-like. This creates incommensurability between the two species along the planes of the layers, resulting in spontaneous symmetry-break periodic ripples in the a-axis orientation. Nevertheless, natural franckeite heterostructure has shown potential for optoelectronic applications mostly because it is a semiconductor with 0.7 eV bandgap, air-stable, and can be easily exfoliated down to ultrathin thicknesses. Here, we demonstrate that few-layer franckeite shows a highly anisotropic nonlinear optical response due to its lattice structure, which allows for the identification of the ripple axis. Moreover, we find that the highly anisotropic third-harmonic emission strongly varies with material thickness. These features are further corroborated by a theoretical nonlinear susceptibility model and the nonlinear transfer matrix method. Overall, our findings help to understand this material and propose a characterization method that could be used in other layered materials and heterostructures to assign their characteristic axes. (c) 2024 Author(s). (AU)

• FAPESP's process: 15/11779-4 - Plasmonic and nonlinear effects in graphene coupled to optical waveguides
• Grantee: Christiano José Santiago de Matos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/04374-6 - Fabrication and characterization of mid-infrared waveguides with graphene nanoribbon arrays
• Grantee: Alisson Ronieri Cadore
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/25339-4 - Integrated photonics devices
• Grantee: Newton Cesario Frateschi
• Support Opportunities: Research Projects - Thematic Grants