University	  of	  Tsukuba	  	  | Center	  for	  Computational	  SciencesQuantum	  Condensed	  Matter	  Physics
ARTED:	  Ab-­‐initio Real	  Time	  Electron Dynamics simulator
Interactions between light and matter are the basis of a wide range of technologies. To gain abasic understanding of the interaction, it is essential to grasp electron dynamics in matter
induced by the light electromagnetic fields in a microscopic scale, 10-­‐9 (nano-­‐)meter in spaceand 10-­‐15 (femto-­‐) second in time. We have been developing a computer code ARTED, Ab-­‐initio
Real Time Electron Dynamics simulator. It is based on time-­‐dependent density functional theory
in microscopic scale. ARTED is available at https://www.github.com/ARTED/ARTED.

Ground	  stateDuring	  laser	  irradiation

Macroscopic system(Electromagnetics)

r2c 2 @t2 A =Microscopic system(Quantum mechanics)
i~@t4⇡J/c=Ĥ

After	  laser	  irradiation

1. ARTED solves coupled dynamics of electrons and electromagnetic fields in a multiscale modeling. In microscopic
scale, time-­‐dependent Kohn-­‐Sham equation is solved in real space grid representation. Maxwell equations for the lightelectromagnetic fields are solved employing finite-­‐difference time-­‐domain method.

3. ARTED is optimized for latest processors ofdifferent architectures. Performances of ARTED(Hamiltonian and stencil operations) arecompared.

2. Electron motion in crystalline
silicon induced by intense andultrashort laser pulse.

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 forscientists and engineers to rely on first-­‐principles calculations to fully understand phenomena from the behavior of electrons. We develop
first-­‐principles calculation code “.”uses real-­‐space finite-­‐difference method for first-­‐principles calculation. The advantages of, which are superior toconventional plane wave methods, are2.	  Applicable	  to	  transport	  calculations.

1.Suitable	  for	  massively	  parallel	  computing.
1000x100

1010100
1000
Number  of  CPUs

reflection

transmission

nanostructure

electrode

yWhole	  System

incident

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 the applicability of the interface
structures.
Resistance	  increases	  by	  oxidation
300GateDrain
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/