Nanodomain fragmentation and local rearrangements in CdSe under pressure

作者：Leoni Stefano^*; Ramlau Reiner; Meier Katrin; Schmidt Marcus; Schwarz Ulrich

来源：Proceedings of the National Academy of Sciences of the United States of America, 2008, 105(50): 19612-19616.

DOI：10.1073/pnas.0805235105

• domains
• metastable phases
• molecular dynamics
• polymorphism
• solid-solid phase transition

Structural transformations in extended solids result from local atomic rearrangements and phase growth mechanisms. A broad class of technologically relevant properties critically depends on local structural issues connected with domain sizes, domain boundary geometries, and defects. However, a precise understanding of structural transformation mechanisms and domain formation is still an open question. Here, we demonstrate the feasibility of very detailed mechanistic investigations in real materials as a prerequisite for intelligent property control. We address the problem of domain fragmentation in bulk CdSe under pressure, jointly by molecular dynamics simulations, high-pressure experiments, and HR-TEM imaging. We show that domain fragmentation is taking place in the high-pressure regime, where nucleation events generate both zinc blende (B3) and wurtzite (B4) structural motifs and, in turn, cause the final lamellar appearance observable by high-resolution TEM. A changed nucleation pattern and a modified B3/B4 ratio represents the system's response to modified external stress conditions.

• 出版日期2008-12-16