University of Tsukuba | Center for Computational Sciences

Quantum 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 range of technologies. For thispurpose, 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 have been developing
an open-source computer code SALMON, Scalable Ab-initio Light-Matter simulator for Optics andNanoscience that describes electron dynamics in molecules, nano-materials, and solids based on firstprinciples time-dependent density functional theory [http://salmon-tddft.jp]. As a novel function ofSALMON, light propagation in nano-materials as well as in bulk medium can be described taking fullaccount of nonlinearity and nonlocality of light-matter interactions in the ab-initio level. We expect
SALMON will be widely used in cutting-edge researches in optics and nanoscience.
(b)

(a)

(a) A multiphysics simulation
solving Maxwell, timedependent Kohn-Sham,and Newton equations isperformed on the Fugaku
system for a thin film ofamorphous SiO2 composedof more than 10,000 atoms.

(b) Weak-scaling
performance on theFugaku system using
up to 27,648 nodes
to simulate 13,648
atoms.

Disclaimer
The results obtained on the evaluation environment in the trial phase do not guarantee the performance, power and other attributes of the supercomputer Fugaku at the start of its public use operation.

Optical Properties of Nano-materials in Real Time and Real Space(a) Optical near-field generated in metal-organic framework, IRMOF-10
When a light pulse irradiates on nano-sized objects, a strong and spatiallylocalized electromagnetic field, which is called the near field, appears around theobject. The near field enables imaging beyond the limit of optical resolution andenhances nonlinear optical processes. We perform first-principles calculations of
the photoexcitation dynamics of an acetylene molecule in a metal organic
framework, IRMOF-10. Resonant laser excitation of the IRMOF-10 generates anoptical near field around the two benzene rings that comprise the main
framework of the IRMOF-10. The second harmonic excitation caused by spatial
nonuniformity of the optical near field is observed.

laser field
I=1010W/cm2
ω=3.38eV

I (W/cm2) 109

1010(b) Optical property of metallic metasurface with sub-nm gaps

1011

1012

Absorption rates

contact address: pr@ccs.tsukuba.ac.jp

Classical

Gap distances

TDDFT

Current distribution

yBy virtue of rapid progresses in fabrications of nano-materials, it ispossible to manufacture periodic materials composed of uniformly
structured nano-objects. Here we investigate the optical propertiesof quantum plasmonic metasurfaces composed of two-dimensional
arrayed metallic nano-spheres with sub-nm gaps according to thetime-dependent density functional theory, a fully quantum
mechanical approach. When the quantum and classicaldescriptions are compared, the absorption rates of themetasurface exhibit substantial differences at shorter gap distances.
The differences are caused by electron transport through the gapsof the nano-objects.

Energy0.4 nmReImx

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