Muon site estimation on La2CuO4 using dipole field and density functional theory calculation

Abstract

It has been nearly 27 years since the discovery of the first high temperature (high-Tc) superconductor on LaBaCuO by Benorz & Muller in 1986 [1], in which the mechanism of how high-Tc superconductor happening remain unsolved up until now. La2CuO4 are a parent compound for La2-xSrxCuO4 superconductor, where show antiferromagnetic behavior on based temperature. By adding Sr doping about 0.05 its properties become superconductor. According to previous experimental and theoretical study [2,3], magnetism plays quite an important role for LaBaCuO. μSR was one of the good tools to investigate magnetic properties of magnetic materials, but its utiliy is limited by the lack of knowledge of the muon implantation site and because of that we need to know where muon was staying on crystals. For many years many methods already proposed to determine the muon site in La2CuO4, but always lead to different sites from one to another. This lead to many confusion for researcher who want to continue and go to deeper understanding about magnetic behavior using μSR. On the present study, we reinvestigated the previous study sites by using dipole field and density functional theory calculation to see the relaxation and energy behavior for each sites. For the dipole calculation we used two kind of magnetic moment from experiment and theoretical, and expand the structure to be 50 Å radius. The potential minima position also included to be tested as the possible muon sites, GGA PBE correction was used to see the different behavior between them. The purpose of this investigation is the first step to find out the general method for muon sites determination, that can applied for many cases. © 2013 AIP Publishing LLC.