Hanchul Kim

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We present an algorithm to reduce the computational complexity for plane-wave codes used in electronic structure calculations. Our proposed algorithm avoids the diagonalization of large Hermitian matrices arising in such problems. The computational time for the diagonalization procedure typically grows as the cube of the number of atoms, or the number of(More)
Predicting the electronic structure of complex systems is an outstanding problem in materials science. If the electronic structure of a given material is known, then many physical and chemical properties can be accurately determined without resorting to experiment. At present, the optical and structural properties of simple solid phases can be predicted(More)
We present an algorithm to reduce the computational complexity for plane-wave codes used in electronic structure calculations. The proposed algorithm avoids the diagonalization of large Hermitian matrices arising in such problems. The computational time for the diagonaliza-tion procedure typically grows as the cube of the number of atoms, or the number of(More)
There are many interests to achieve long-range magnetic order in topological insulators of Bi2Se3 or Bi2Te3 by doping magnetic transition metals such as Fe and Mn. The transition metals act as not only magnetic dopants but also electric dopants because they are usually divalent. However, if the doping elements are rare-earth metals such as Gd, which are(More)
The recently developed spin-dependent pseudopotentials markedly improve the description of the energetics of isolated transition metal atoms ͓S.dependent pseudopotentials are obtained from a combination of spin-neutral and fully polarized atomic pseudo-potentials, employing the self-consistent local spin polarization to adapt to different environments.(More)
We discuss our new implementation of the Adaptive Coordinate Real-space Electronic Structure (ACRES) method for studying the atomic and electronic structure of infinite periodic as well as finite systems, based on density functional theory. This improved version aims at making the method widely applicable and efficient, using high performance Fortran on(More)
Action-derived molecular dynamics for the simulation of rare event and slow mode systems is reviewed. Theoretical background, implementation details, and comparison with other methods are presented. Numerical examples demonstrated include the structural formation and transformation of carbon fullerenes, and molecular reconfiguration of alanine dipeptide and(More)
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