RealSuper · Realistic modeling of unconventional superconductors

Feynman diagrammatic extensions of dynamical mean-field theory are powerful enough for calculating unconventional superconductivity in actual materials. As a proof of principle, we were able to predict the superconducting phase diagram,the electronic and magnetic spectra of infinite-layer nickelates - with astonishing accuracy. At the same time, a new class of finite-layer nickelates, La_n+1Ni_nO_3n+1, was discovered last year. These Ruddlesden-Popper nickelates led to a boost of scientific activity and put common wisdom of superconductivity in nickelates and cuprates into question, as clearly multi Ni orbitals are relevant.Our objective is to (1) realistically model superconductivity in these finite-layer nickelates and in cuprates, to achieve a similarly good agreement with experiment as for infinite-layer nickelates, and to quantify the relative importance of spin and charge fluctuations. We will validate our calculations against a carefully selected variety of experiments: photoemission and optical spectroscopy, neutron and resonant inelastic x-ray scattering, the superconducting temperature Tc and gap, its doping and pressure dependence. If successful and achieving a consistent picture, we can settled the arguably biggest quest of solid state theory: the physical origin of high-Tc superconductivity. Already in the normal phase, we can (2) study exciting physics: pseudogaps, waterfalls, strange metal behavior, pi-tons, spin and charge density wave order. With an improved understanding of high-Tc superconductivity, a further aim is to (3) eventually predict how to optimize superconductivity in nickelates and cuprates and even to identify new classes of superconductors. Advancing our understanding and developing a predictive power is how theory can contribute to push Tc toward room temperature, which bears the prospects to revolutionize how we generate, transport and consume electric energy.