Estimation of the on-site Coulomb potential and covalent state in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>La</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>CuO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math> by muon spin rotation and density functional theory calculations
Muhammad Redo Ramadhan, Budi Adiperdana, Irwan Ramli, Dita Puspita Sari, Anita Eka Putri, Utami Widyaiswari, Harison Rozak, Wan Nurfadhilah Zaharim, Azwar Manaf, Budhy Kurniawan, Mohamed Ismail Mohamed–Ibrahim, Shukri Sulaiman, Takayuki Kawamata, Tadashi Adachi, Yōji Koike, Isao Watanabe
Abstract
The on-site Coulomb potential, $U$, and the covalent state of electronic orbitals play key roles for the Cooper pair symmetry and exotic electromagnetic properties of high-${T}_{\mathrm{c}}$ superconducting cuprates. In this paper, we demonstrate a way to determine the value of $U$ and present the whole picture of the covalent state of Cu spins in the mother system of the La-based high-${T}_{\mathrm{c}}$ superconducting cuprate, ${\mathrm{La}}_{2}{\mathrm{CuO}}_{4}$, by combining the muon spin rotation $(\ensuremath{\mu}\mathrm{SR})$ and the density functional theory (DFT) calculation. We reveal local deformations of the ${\mathrm{CuO}}_{6}$ octahedron followed by changes in Cu-spin distributions caused by the injected muon. Adjusting the DFT and $\ensuremath{\mu}\mathrm{SR}$ results, $U$ and the minimum charge-transfer energy between the upper Hubbard band and the O $2p$ band were optimized to be 4.87(4) and 1.24(1) eV, respectively.