Fig. 1: Structure determination of BaMnSb2.
From: Spin-valley locking and bulk quantum Hall effect in a noncentrosymmetric Dirac semimetal BaMnSb2
a The schematic showing the I2mm crystal structure of BaMnSb2. b Schematic of the Sb zig-zag chain layer from [001] and [010] axis formed due to orthorhombic distortion. c Simulated (left panel) and experimental (right panel) HAADF-STEM images along the [100] and [010] zone axes. d Magnified experimental HAADF-STEM image with superimposed atom structures highlighting the orthorhombic distortion. The red arrows point to the Sb layer and show how Sb atoms in the zig-zag chain layer form dimmer-like structure in the STEM image taken along the [010]-zone axis. e Optical SHG microscopy of polar domains. The polar axes are indicated by the light blue arrows. The imaging light polarization conditions for the ω and the 2ω frequencies are indicated by red and purple arrows. The crystallographic axes in each domain are indicated. The light polarization conditions for the inset image are orthogonal to the corresponding conditions for the main image, hence the reversal in contrast that is observed. f SHG polarimetry experiments (circles) in domains A and B indicated in panel (e), and the corresponding theoretical fits (solid lines) are shown for two different SHG polarization directions indicated in the inset schematic. Details of the fit based on 2mm point group symmetry are given in Supplementary Note 1.
