Tuning carrier density via magnetic correlations in NdNiO$_2$: a practical mean to resolve the nature of hole carriers

Recently discovered unconventional superconductor Nd$_{0.8}$Sr$_{0.2}$NiO$_2$ demonstrated many traits similar to the prototypical cuprates. Yet, density functional theory (DFT) calculations suggest two noticeable differences: existence of electron carriers in Nd-$d$ orbitals, and potential importance of Ni-$d_{z^2} orbital in hosting hole carriers. Here, we examine the impacts of in-plane and out-of-plane magnetic correlations on the DFT+$U$ electronic structures, under various non-collinear thermal fluctuation. Our results demonstrate strong tuning of the kinetic energy of the key orbitals of Nd, Ni, and O, resulting a dramatic modification of carrier density. In contrast, such sensitivity to magnetic correlation should be absence in the competing many-body picture of singlet formation. Therefore, this effect points to sensitive experimental means to verify (or falsify) the current theoretical debate on the nature of the hole carriers in this system, for example via uniaxial pressure.