Linear Scaling 3D Fragment Method for Large-Scale ElectronicStructure Calculations

We present a linear scaling 3 dimensional fragment (LS3DF)method that uses a novel decomposition and patching scheme to do abinitio density functional theory (DFT) calculations for large systems.This method cancels out the artificial boundary effects that arise fromthe spatial decomposition. As a result, the LS3DF results are essentiallythe same as the original full-system DFT results with errors smaller thanthe errors introduced by other sources of numerical approximations. Inaddition, the resulting computational times are thousands of timessmaller than conventional DFT methods, making calculations with 100,000atom systems possible. The LS3DF method is applicable to insulator andsemiconductor systems, which covers a current gap in the DOE's materialsscience code portfolio for large-scale ab initio simulations