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Large-scale DFT study of complex nano-scale materials using CONQUEST

Abstract: First-principles calculations based on the density functional theory (DFT) have been playing important roles to clarify the atomic structures and electronic properties of various materials. However, conventional DFT methods cannot treat large and complex systems containing many thousands of atoms, since the calculation cost increases rapidly when the number of atoms in a target system becomes large. To overcome this size limitation in DFT calculations, we have developed a large-scale and linear-scaling DFT code CONQUEST1). The code has high efficiency on massively parallel computers, and it is possible to perform DFT calculations of million-atom systems. In this talk, I will show the overview of the code and introduce some of the recent applications. It will be demonstrated that CONQUEST can calculate the structures of complex nano-scale materials observed in experiments at atomic scale and can clarify the unique electronic properties of these materials. A new method based on the machine learning techniques to analyse the local atomic structures observed in large-scale DFT-MD simulations will be also discussed2). CONQUEST is now open to public3) under the MIT license. This work has been done in collaboration with D. R. Bowler (UCL, UK), A. Nakata, S. Li, A. Yatmeidhy, M. Tamura (NIMS, Japan), L. Truflandier (U. Bordeaux, France), A.K.A. Lu (U. Tokyo, Japan), Y. Futamura and T. Sakurai (U. Tsukuba, Japan).