Simulations of pressure-induced phase transitions in amorphous<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>Si</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi mathvariant="normal">C</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>alloys

Иващенко, В. И.; Turchi, P. E. A.; Шевченко, В. И.; Ivashchenko, L. A.; Shramko, O. A.

doi:10.1103/physrevb.71.165209

Cited by 8 publications

(15 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The calculated Gibbs free energy curves confirm the conclusion of Durandurdu and Drabold on the impossibility of a phase transition between ␤-Si and the HDA phase. 26 We obtained a slightly lower value P 0 for the a-Si→ HDA transition than in our earlier work, 40 and this can be attributed to an improved structure of a-Si and to a slightly more appropriate relaxation procedure used in the present investigation.…”

Section: Pressure-induced Phase Transformationscontrasting

confidence: 48%

“…The details of the computations with the orthogonal sp 3 s Ã TB scheme were described elsewhere. 40 In previous studies [40][41][42] it was shown that the set of TB two-center parameters that were used in the TB-MD simulations provided reasonable atomic and electronic structures for silicon-based amorphous alloys. In this work, the eigenvalues were calculated at the ⌫ point of the Brillouin zone, which is reasonable for a cubic cell with 512 atoms.…”

Section: Simulation Setupmentioning

confidence: 99%

“…The a-Si and HDA structures were generated according to the procedure described in Ref. 40. The transition pressure between two silicon phases at zero temperature was calculated from wellknown thermodynamics and from the computed P-V dia-grams.…”

Section: Simulation Setupmentioning

confidence: 99%

“…It is well known that in a-Si, gap states arise due to abnormally coordinated atoms or strongly distorted fourfold configurations. 40 Uniaxial compression of cd-Si leads to a widening of the valence and conduction bands. As a result, the cd-Si phase just before ST ͑P = 10 GPa͒ is a semiconductor with a narrow band gap.…”

Section: Indentation-induced Semiconductor-to-metal Transitionsmentioning

confidence: 99%

“…The phase after ST ͑P = 12 GPa͒ is ␤-Si, and its electronic spectrum consists of extended states that give rise to metallic conductivity. During triaxial compression of a-Si, a change in conductivity from semiconducting to metallic occurs at P =8-10 GPa 25,26,40 and is due to the formation of a HDA phase. As in the case of ␤-Si, the extended states are responsible for the metallic conductivity of the HDA phase ͑cf.…”

Section: Indentation-induced Semiconductor-to-metal Transitionsmentioning

confidence: 99%

See 4 more Smart Citations

Simulations of indentation-induced phase transformations in crystalline and amorphous silicon

2008

Self Cite

View full text Add to dashboard Cite

The pressure-and indentation-induced phase transformations in crystalline ͑cd͒ and amorphous ͑a͒ silicon are studied by using molecular dynamics simulations based on the modified Tersoff potential. The sp 3 s Ã tight-binding scheme is employed to gain insight into the origin of the change in conductivity during nanoindentation. The Gibbs free energy calculations predict the following pressure-induced phase transitions: cd-Si → ␤-tin Si͑␤-Si͒ ͑11.4 GPa͒; cd-Si→ high density amorphous phase ͑HDA͒ ͑22.5 GPa͒; a-Si→ ␤-Si ͑2.5 GPa͒; a-Si→ HDA ͑8.4 GPa͒. Simulations of nanoindentation of crystalline silicon reveal discontinuities in the load-displacement curves. In the loading curves of the cd-Si ͑100͒ substrate, the pop-in is assigned to the appearance of the ␤-tin Si phase. During unloading, the pop-out is due to the formation of a low-density amorphous phase a-Si. The a-Si→ HDA transformation takes place during nanoindentation of a-Si in loading regime. Upon unloading the a-Si phase is preserved. The structural transformations in cd-Si and a-Si during nanoindentation are treated in terms of triaxial and uniaxial compressions of the respective bulk samples. A change in conductivity from semiconducting to metallic during nanoindentation of the cd-Si ͑100͒ and a-Si slabs is explained in terms of a transformation of the localized electronic states in the band gap region. The results are compared to those of available theoretical models and experiments.

show abstract

Section: Pressure-induced Phase Transformationscontrasting

confidence: 48%