scholarly journals Linear-scaling density-functional simulations of charged point defects in Al2O3 using hierarchical sparse matrix algebra

2010 ◽  
Vol 133 (11) ◽  
pp. 114111 ◽  
Author(s):  
N. D. M. Hine ◽  
P. D. Haynes ◽  
A. A. Mostofi ◽  
M. C. Payne
Keyword(s):  
Point Defects ◽  
Density Functional ◽  
Matrix Algebra ◽  
Sparse Matrix ◽  
Linear Scaling ◽  
Charged Point

scholarly journals Parallel Implementation of Large-Scale Linear Scaling Density Functional Theory Calculations With Numerical Atomic Orbitals in HONPAS

2020 ◽  
Vol 8 ◽  
Author(s):  
Zhaolong Luo ◽  
Xinming Qin ◽  
Lingyun Wan ◽  
Wei Hu ◽  
Jinlong Yang
Keyword(s):  
Density Matrix ◽  
Dft Calculations ◽  
Density Functional ◽  
Large Scale ◽  
Parallel Implementation ◽  
Sparse Matrix ◽  
Matrix Multiplication ◽  
Linear Scaling ◽  
Functional Theory ◽  
Atomic Orbitals

Linear-scaling density functional theory (DFT) is an efficient method to describe the electronic structures of molecules, semiconductors, and insulators to avoid the high cubic-scaling cost in conventional DFT calculations. Here, we present a parallel implementation of linear-scaling density matrix trace correcting (TC) purification algorithm to solve the Kohn–Sham (KS) equations with the numerical atomic orbitals in the HONPAS package. Such a linear-scaling density matrix purification algorithm is based on the Kohn's nearsightedness principle, resulting in a sparse Hamiltonian matrix with localized basis sets in the DFT calculations. Therefore, sparse matrix multiplication is the most time-consuming step in the density matrix purification algorithm for linear-scaling DFT calculations. We propose to use the MPI_Allgather function for parallel programming to deal with the sparse matrix multiplication within the compressed sparse row (CSR) format, which can scale up to hundreds of processing cores on modern heterogeneous supercomputers. We demonstrate the computational accuracy and efficiency of this parallel density matrix purification algorithm by performing large-scale DFT calculations on boron nitrogen nanotubes containing tens of thousands of atoms.

Energetics of charged point defects in rutile TiO2 by density functional theory

2009 ◽  
Vol 57 (19) ◽  
pp. 5882-5891 ◽  
Author(s):  
X. Li ◽  
M.W. Finnis ◽  
J. He ◽  
R.K. Behera ◽  
S.R. Phillpot ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Point Defects ◽  
Density Functional ◽  
Functional Theory ◽  
Rutile Tio2 ◽  
Charged Point

scholarly journals Imaging and identification of point defects in PtTe2

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Kuanysh Zhussupbekov ◽  
Lida Ansari ◽  
John B. McManus ◽  
Ainur Zhussupbekova ◽  
Igor V. Shvets ◽  
...  
Keyword(s):  
Point Defects ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Density Functional Theory Calculations ◽  
Charge Carrier Mobility ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Recombination Rates ◽  
And Performance

AbstractThe properties and performance of two-dimensional (2D) materials can be greatly affected by point defects. PtTe2, a 2D material that belongs to the group 10 transition metal dichalcogenides, is a type-II Dirac semimetal, which has gained a lot of attention recently due to its potential for applications in catalysis, photonics, and spintronics. Here, we provide an experimental and theoretical investigation of point defects on and near the surface of PtTe2. Using scanning tunneling microscopy and scanning tunneling spectroscopy (STS) measurements, in combination with first-principle calculations, we identify and characterize five common surface and subsurface point defects. The influence of these defects on the electronic structure of PtTe2 is explored in detail through grid STS measurements and complementary density functional theory calculations. We believe these findings will be of significance to future efforts to engineer point defects in PtTe2, which is an interesting and enticing approach to tune the charge-carrier mobility and electron–hole recombination rates, as well as the site reactivity for catalysis.

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