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Résumé |
A major challenge of our time is to develop new pathways for energy
transformation, storage, and use. This "energy frontier research", aiming
at design, synthesis, and manufacture with higher performance and
functionality, requires scientific innovative observations far beyond
incremental advances in current energy technologies. Traditionally, basic
science has relied on two variables or dimensions (namely temperature and
composition) of known materials to understand underlying physics.
Pressure is regarded as an entirely new dimension of science, which
enables us to explore much broader range of thermo-mechanical conditions by accessing extreme states of matter.
In this presentation, I will show recent progress on our theory-experiment
collaborative works in this direction. Crystal structure searching using
density functional theory predicts possible novel phases and guides our
experiments. Experimental observations provide inputs for refinement of
calculations. I will present our recent successful examples to highlight
the importance of integrated experiment-theory collaboration for Energy
Frontier Research. Especially, I will show our recent discovery of a new
silicon allotrope with an orthorhombic structure which is stabilized at
ambient conditions. Interestingly, it possesses a quasi-direct band-gap
with ~ 1.3 eV, which is the optimal band-gap for photovoltaic applications.
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