Lithiation Induced Phases in 1T'-MoTe₂ Nanoflakes.

Abstract

Multiple polytypes of MoTe₂ with distinct structures and intriguing electronic properties can be accessed by various physical and chemical approaches. Here, we report electrochemical lithium (Li) intercalation into 1T'-MoTe₂ nanoflakes, leading to the discovery of two previously unreported lithiated phases. Distinguished by their structural differences from the pristine 1T' phase, these distinct phases were characterized using <i>in situ</i> polarization Raman spectroscopy and <i>in situ</i> single-crystal X-ray diffraction. The lithiated phases exhibit increasing resistivity with decreasing temperature, and their carrier densities are two to 4 orders of magnitude smaller than the metallic 1T' phase, as probed through <i>in situ</i> Hall measurements. The discovery of these gapped phases in initially metallic 1T'-MoTe₂ underscores electrochemical intercalation as a potent tool for tuning the phase stability and electron density in two-dimensional (2D) materials.