Fig. 2: Structure and carrier evolution across Cu substitution.
From: Suppression of intertwined density waves in La4Ni3-xCuxO10+δ
a A high angle annular dark field (HAADF) scanning transmission electron microscopy image of an undoped La4Ni3O10+δ polycrystalline sample is shown alongside the monoclinic phase of La4Ni3O10 in the ac-plane. b Lattice parameters versus Cu content: a (left axis, black) and b, c (right axis, orange/brown). Symbols are refined values; dashed lines are linear fits. Colored horizontal arrows indicate the corresponding axes. c Ni-O-Ni bond angle as a function of x; symbols are refined values and the dashed line is a linear fit showing a monotonic decrease with doping. d Carrier concentration n from Hall measurements at 1.8 K (green circles) compared with the value expected from oxygen non-stoichiometry assuming full ionization of excess oxygen (red squares). Blue diamonds show δ from TGA. Dotted lines are linear guides; the green annotations highlight the initial increase of n (0 ≤ x ≤ 0.36) and the subsequent plateau at higher x.
