Abstract
Ordinary materials can transform into novel phases at extraordinary high pressure and temperature. The recently developed method of ultrashort laser-induced confined microexplosions initiates a non-equilibrium disordered plasma state. Ultra-high quenching rates overcome kinetic barriers to the formation of new metastable phases, which are preserved in the surrounding pristine crystal for subsequent exploitation. Here we demonstrate that confined microexplosions in silicon produce several metastable end phases. Comparison with an ab initio random structure search reveals six energetically competitive potential phases, four tetragonal and two monoclinic structures. We show the presence of bt8 and st12, which have been predicted theoretically previously, but have not been observed in nature or in laboratory experiments. In addition, the presence of the as yet unidentified silicon phase, Si-VIII and two of our other predicted tetragonal phases are highly likely within laser-affected zones. These findings may pave the way for new materials with novel and exotic properties.
Original language | English |
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Article number | 7555 |
Journal | Nature Communications |
Volume | 6 |
DOIs | |
State | Published - Jun 29 2015 |
Funding
We would like to thank V.V. Brazhkin for valuable discussions. This research was supported under the Australian Research Council’s Discovery Project funding scheme (project DP120102980). Partial support to this work by Air Force Office of Scientific Research, USA, (FA9550-12-1-0482) is gratefully acknowledged. We also acknowledge the ANFF ACT Node for the access to their FIB system and the AMMRF for access to their TEM. J.E.B. is funded under the Australian Research Council’s Future Fellow Scheme. B.H. gratefully acknowledges current funding from an Alvin M. Weinberg Fellowship (ORNL) and the Spallation Neutron Source (ORNL), sponsored by the U.S. Department of Energy, Office of Basic Energy Sciences. C.J.P. was supported by the Engineering and Physical Sciences Research Council of the UK (EP/G007489/2).