Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Alejandro Lopez Bezanilla Project Name: Irridates Division: PSE Project title: Metal-insulator phase transitions in irridates Associated funding: DoE Other Systems: Science: Pyrochlore iridates (R2Ir2O7 where R is rare earth element or Y) are a paradigm system for studying the interplay of spin-orbit coupling and electron correlation, potentially leading to important topological effects in the electronic structure. Theoretical model-system calculations have reported interesting phases including chiral spin liquids, Weyl semimetal, and axion insulators. Systematic experimental studies have been also conducted for these compounds and revealed a strong dependence of physical properties on the choice of rare earth/alkali ion R. In our previous LCRC work we performed realistic density functional plus dynamical mean field (DFT+DMFT) calculations we obtained an ab-initio many-body phase diagram in the plane of chemical composition and on-site interaction U that features metallic magnetic phases with all-in/all-out magnetic ordering and electronic structure characterized by tilted Weyl cones, and we studied the R-dependence of the metal-insul ator transitions, concluding that intersite effects normally neglected in DFT+DMFT calculations play an important role in understanding material-dependence in experiments for the Y and Eu compound. Project description: We request an additional allocation of 490,000 CPU hours to continue and extend our DFT+DMFT studies of pyrochlore materials with strong spin-orbit coupling and electron correlations. The pyrochlore oxide Cd2Re2O7 is of intense current interest because it is a correlated material that undergoes a continuous phase transition at a temperature T=200K from an ideal pyrochlore structure to a distorted, parity-violating structure. The energetics and indeed the physics of this transition are the subject of intense current interest, with the relative importance of lattice-driven displace effects and multipolar nematicity now debate. We aim to apply state of the art many-body methods to obtain an understanding of the electronic structure of both phases of this material and to obtain an estimate of the energetics of the transition. Cd2Re2O7 has a similar crystal structure to the pyrochlore iridates (R2Ir2O7) that were the subject of our previous density functional plus dynamical means theory studies. Building on our previous work, we will carry out fully relativistic DFT calculations, including on-site U via the DFT+U method, for the 2 structures above and below transition, and then building on these results we will first verify that the J=1/2 and 3/2 band complexes are sufficiently separated, so that a frontier orbital approach similar to that used in the irradiates applies. Assuming it does we will perform 4-site cluster DMFT calculations. If the orbitals cannot be separated we will include the entire J- multiplets and perform single-site DMFT calculations. The exact diagonalization (ED) impurity solver will be employed to solve the self consistent equations in DMFT. This solver has been developed and validated in our previous study of pyrochlore iridates and it enables access to large clusters and a greate number of bath orbitals which makes cluster calculations of this type possible. According to our experience from pyrochlore iridates, we propose to use eight correlated and sixteen bath orbitals, for a reasonable accuracy. According to previous cluster DMFT calculations on Blues, a single DMFT iteration takes 128 CPU hours (0.5 hour with 256 cores). The number of iterations for a converged solution largely depends on the external parameters (U: Coulomb interaction, mu: chemical potential) and the initial condition, but it is usually between 10 to 100. Therefore, we count about 5k CPU hours for a typical calculation. For each structure, we will run the calculations with different sets of external parameters and the initial condition, as much as the allocation allows. In total, the calculates will require 490,000 CPU hours. We will use software already installed and tested in LCRC clusters to perform the DFT and DMFT calculations, which require LAPACK, CLAPACK, GSL, BLAS and OPENMPI packages (all available on Blues and Bebop). For the DFT calculations we will use VASP_5 or the latest version of the code in Bebop once compatibility has been checked. We are currently porting and testing our codes to Bebob. We intend to intensively use the new cluster. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 495000 Q1: 125000 Q2: 125000 Q3: 125000 Q4: 120000 Justification: Storage requirements: 1 TB Thank You, The LCRC Accounts System