University	  of	  Tsukuba	  	  | Center	  for	  Computational	  SciencesQuantum	  Condensed	  Matter	  Physics
SALMON:	  Scalable	  Ab-­‐initio	  Light-­‐Matter	  simulator	  for	  Optics	  and	  Nanoscience
Understanding interaction between light and matter is the basis of a wide (a)range of technologies. For this purpose, it is essential to describe electron
dynamics in matters induced by light electromagnetic fields in a microscopic
scale, 10-­‐9 (nano-­‐)meter in space and 10-­‐15 (femto-­‐) second in time. We havebeen developing an open-­‐source computer code SALMON, Scalable Ab-­‐initio
Light-­‐Matter simulator for Optics and Nanoscience that describes electron
dynamics in molecules, nano-­‐materials, and solids based on first-­‐principles
time-­‐dependent density functional theory [http://salmon-­‐tddft.jp].
(b)

(c)

|E(r, t)|laser	  field
I=1010W/cm2
ω=3.38eVI	  (W/cm2)

Macroscopic	  system	  (EM	  field)

109

1010

1011

Microscopic	  system	  (TDDFT)

2⇢(r, t)(a) Performance	  of	  SALMON	  using	  full	  nodes	  of	  Oakforest-­‐PACS.
(b) Optical	  near-­‐field	  generated	  in	  metal-­‐organic	  framework,	  IRMOF10.
(c) Intense	  pulsed	  light	  irradiates	  on	  silicon	  nano-­‐sphere	  of	  250nm	  radius	  by	  coupled	  Maxwell-­‐TDDFT	  calculation.

1012

Computational	  Design	  of	  Future	  Electronics	  Devices	  using	  First-­‐Principles	  Calculations
With cutting-­‐edge materials and minute electronic devices being produced by the latest nanoscale fabrication technology, it
is essential for scientists and engineers to rely on first-­‐principles calculations to fully understand phenomena from thebehavior of electrons. We develop first-­‐principles calculation code “.”uses real-­‐space finite-­‐difference method for first-­‐principles calculation. The advantages of, which aresuperior to conventional plane wave methods, are2.	  Applicable	  to	  transport	  calculations.
1.Suitable	  for	  massively	  parallel	  computing.
1000

incident

x100

reflection

1010100
1000
Number  of  CPUs

transmission

nanostructure

electrodeyWhole	  System

Si bulk (1000 atoms)  Si  bulk  (1000  atoms)

electrodez

Computation  time  (sec)

H22O
Cluster (96 stoms)  H
O  Cluster  (96  atoms)

10000

As applications using, interface atomic structures are examined and fabrication procedures are developed to realize
high-­‐performance and low-­‐energy-­‐loss electronic devices, e,g., SiC power devices. By investigating the origin of leakage
current and carrier scattering at interfaces, we propose prescriptions to improve device performance and demonstrate theapplicability of the interface structures.
Resistance	  increases	  by	  oxidation
300

Gate

Drain
Current	  (µA)

Source200
10000.0

SiC device

Scattering	  of	  carrier	  due	  to	  interface	  defects

Initial	  interface
Oxidation1
Oxidation2
Oxidation3

0.5
Bias	  (V)

Carrier	  scattering	  property	  obtained	  by	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  	  .

1.0Computational	  design	  of	  interface	  structure

Furthermore, we establish a basic technology of computational science to design interface structures and fabrication
procedures of future electronic devices.
contact	  address:	  pr@ccs.tsukuba.ac.jp

http://www.ccs.tsukuba.ac.jp/