Structural Engineering Commons^™

Naturally Occurring Van Der Waals Heterostructure Lengenbachite With Strong In-Plane Structural And Optical Anisotropy, Arindam Dasgupta, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lengenbachite is a naturally occurring layered mineral formed with alternating stacks of two constituent PbS-like and M₂S₃-like two-dimensional (2D) material layers due to the phase segregation process during the formation. Here, we demonstrate to achieve van der Waals (vdW) heterostructures of lengenbachite down to a few layer-pair thickness by mechanical exfoliation of bulk lengenbachite mineral. The incommensurability between the constituent isotropic 2D material layers makes the formed vdW heterostructure exhibit strong in-plane structural anisotropy, which leads to highly anisotropic optical responses in lengenbachite thin flakes, including anisotropic Raman scattering, linear dichroism, and anisotropic third-harmonic generation. Moreover, …