TY - JOUR
T1 - Kinetic origin of divergent decompression pathways in silicon and germanium
AU - Wang, Jian Tao
AU - Chen, Changfeng
AU - Mizuseki, Hiroshi
AU - Kawazoe, Yoshiyuki
PY - 2013/4/15
Y1 - 2013/4/15
N2 - Silicon and germanium transform from diamond to β-tin structure under compression, but upon decompression they turn into metastable BC8 Si and ST12 Ge phases, respectively, instead of returning to the lowest-enthalpy diamond structure. Here we explore by first-principles calculations the atomistic mechanism underlying this intriguing phenomenon. We identify a body-centered tetragonal structure in I41/a (C4h6) symmetry as a precursory state of the BC8 Si phase formed via a double cell bond-rotation mechanism with a low kinetic barrier. Kinetics also play a central role in selecting the decompression pathway in Ge via a trinary cell bond-twisting reconstruction process toward the ST12 Ge phase. In both cases, transformation back to energetically more favorable diamond structure is inhibited by the higher enthalpy barrier. These results explain experimental findings and highlight the kinetic origin of the divergent decompression pathways in Si and Ge.
AB - Silicon and germanium transform from diamond to β-tin structure under compression, but upon decompression they turn into metastable BC8 Si and ST12 Ge phases, respectively, instead of returning to the lowest-enthalpy diamond structure. Here we explore by first-principles calculations the atomistic mechanism underlying this intriguing phenomenon. We identify a body-centered tetragonal structure in I41/a (C4h6) symmetry as a precursory state of the BC8 Si phase formed via a double cell bond-rotation mechanism with a low kinetic barrier. Kinetics also play a central role in selecting the decompression pathway in Ge via a trinary cell bond-twisting reconstruction process toward the ST12 Ge phase. In both cases, transformation back to energetically more favorable diamond structure is inhibited by the higher enthalpy barrier. These results explain experimental findings and highlight the kinetic origin of the divergent decompression pathways in Si and Ge.
UR - http://www.scopus.com/inward/record.url?scp=84876262314&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84876262314&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.110.165503
DO - 10.1103/PhysRevLett.110.165503
M3 - Article
AN - SCOPUS:84876262314
VL - 110
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 16
M1 - 165503
ER -