First-principles electronic structure investigation of HgBa2Can−1CunO2n+2+x with the SCAN density functional

We perform first-principles calculations to study the electronic structure of HgBa2Can−1CunO2n+2+x copper oxides up to n = 6 for the undoped parent compound (x = 0) and up to n = 3 for the doped compound (x > 0) by means of the strongly constrained and appropriately normed (SCAN) density functional. Our calculations predict an antiferromagnetic insulator ground state for the parent compounds with an energy gap that decreases with the number of CuO2 planes. We report structural, electronic, and magnetic order evolution with x, which agrees with the experiments. We find an enhanced density of states at the Fermi level at x ≈ 0.25 for the single-layered compound. This manifests in a peak of the Sommerfeld parameter of electronic specific heat, which has recently been discussed as a possible signature of quantum criticality generic to all cuprates.