Fig. 2: Atomic structure and layer-dependent inversion symmetry breaking of MoTe2 film.
From: Growth of bilayer MoTe2 single crystals with strong non-linear Hall effect
a, b Aberration-corrected scanning transmission electron microscopy images (a) and corresponding simulated atomic structure (b) of bilayer 1T′ MoTe2. The scale bar is 1 nm. c–e Atomic force microscope images of MoTe2 with different layers, showing the thickness of monolayer with 0.7 nm (c), epitaxially grown 0.7 nm-thick second layer on top of the monolayer (d), and 2.1 nm-thick trilayer (e). All the scale bars are 1 μm. f, Second-harmonic generation measurement of MoTe2 with different layers. g–i Topography (g), phase (h), and amplitude (i) images of bilayer 1T′ MoTe2 single crystals recorded after polarization switching with DC bias +5 V in the central region of 5 μm followed by −5 V in the central region of 2 μm. All the scale bars are 2 μm. j Phase (blue curve) and amplitude (red curve) signals as a function of the tip voltage for the selected points, showing local hysteresis and butterfly loops.
