fig2

Figure 2. DFT calculated PDOS and the simulated STM images of the pristine Na₂IrO₃ surface. (A) The calculated PDOS of the top Na layer (red, 1st-Na), the second O layer (black, 2nd-O) and the Ir (blue, 3rd-Ir) in the third layer, respectively. The inset shows the schematic crystal field splitting of the 5d level in the half-filling case with J_eff = 1/2. (B) The simulated empty (+2.0 eV) and filled (-2.0 eV) state STM images using an Ir(111) tip. The superimposed Na, O and Ir atoms are represented with blue, red and pink balls, respectively. (C) Experimental STM images acquired at +2.0 V (left) and -2.0 V (right), respectively. The unit cells of the honeycomb lattice of the Na₂IrO₃ surface are indicated with cyan hexagons.