dc.contributor.author 
Li, X 

dc.contributor.author 
Lin, L 

dc.contributor.author 
Lu, Jianfeng 

dc.date.accessioned 
20170423T15:47:13Z 

dc.date.available 
20170423T15:47:13Z 

dc.date.issued 
20170423 

dc.identifier 
http://arxiv.org/abs/1606.00515v2 

dc.identifier.uri 
https://hdl.handle.net/10161/14057 

dc.description.abstract 
In this paper, we propose a new Green's function embedding method called PEXSI$\Sigma$
for describing complex systems within the KohnSham density functional theory (KSDFT)
framework, after revisiting the physics literature of Green's function embedding methods
from a numerical linear algebra perspective. The PEXSI$\Sigma$ method approximates
the density matrix using a set of nearly optimally chosen Green's functions evaluated
at complex frequencies. For each Green's function, the complex boundary conditions
are described by a self energy matrix $\Sigma$ constructed from a physical reference
Green's function, which can be computed relatively easily. In the linear regime, such
treatment of the boundary condition can be numerically exact. The support of the $\Sigma$
matrix is restricted to degrees of freedom near the boundary of computational domain,
and can be interpreted as a frequency dependent surface potential. This makes it possible
to perform KSDFT calculations with $\mathcal{O}(N^2)$ computational complexity, where
$N$ is the number of atoms within the computational domain. Green's function embedding
methods are also naturally compatible with atomistic Green's function methods for
relaxing the atomic configuration outside the computational domain. As a proof of
concept, we demonstrate the accuracy of the PEXSI$\Sigma$ method for graphene with
divacancy and dislocation dipole type of defects using the DFTB+ software package.


dc.subject 
physics.compph 

dc.subject 
physics.compph 

dc.subject 
math.NA 

dc.subject 
physics.chemph 

dc.title 
PEXSI$Σ$: A Green's function embedding method for KohnSham density functional theory 

dc.type 
Journal article 

pubs.authorurl 
http://arxiv.org/abs/1606.00515v2 

pubs.organisationalgroup 
Chemistry 

pubs.organisationalgroup 
Duke 

pubs.organisationalgroup 
Mathematics 

pubs.organisationalgroup 
Physics 

pubs.organisationalgroup 
Trinity College of Arts & Sciences 
