Figure7

Figure 7. Total phase image of Ca₃Co₃O₈ measured at room temperature^[93]. The bar charts show averaged experimental relative shifts ($$ d_{CoO} $$) along the c axis between the Co atom and neighbor equatorial O atoms at two different octahedral layers (at room temperature), and the calculated results for different magnetic states. The net relative shift is a summation between these two layers, which is notably larger than the standard error. The illustration indicates the coupling between the build-in OOP electric field E and IP spins S, resulting in a Rashba spin–orbit coupling. The E and E' with opposite directions are not equal in magnitude as a result of the broken mirror (m) symmetry. Experimental data are presented as mean values ± standard error of the mean (error bar) from the relative shifts of n = 20 Co atoms. The purple, yellow and red circles represent the calcium, cobalt and oxygen atoms, respectively.