Can Corrugated Si-Planes of CaSi_2 Flatten under High Pressure?
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Stability and structural transformation under high pressure are investigated for polymorphs of calcium di-silicide (CaSi<SUB>2</SUB>) theoretically. Using LDA calculalculaaaaation we can show that sp<SUP>2</SUP>-bonded structures are stabilized at high pressure against popular trigonal structure with sp<SUP>3</SUP>-bonded corrugated Si-planes. Our result suggests that even AlB<SUB>2</SUB> structure with flat honeycomb Si-planes, which has not been found for CaSi<SUB>2</SUB> experimentally, could be obtained under high pressure at low temperature. Characteristics of structural transformation of CaSi<SUB>2</SUB> is discussed in comparison with the graphite-diamond transformation in which sp<SUP>3</SUP> bonding is selected at high pressure.
- The Review of High Pressure Science and Technology
The Review of High Pressure Science and Technology 7, 193-195, 1998
The Japan Society of High Pressure Science and Technology