Abstract:
:The high-pressure behavior of amorphous selenium has been investigated with time-resolved diamond anvil cell synchrotron x-ray diffraction and computed microtomography techniques. A two-step dynamic crystallization process is observed in which the monoclinic phase crystallized from the amorphous selenium and gradually converted to the trigonal phase, thereby explaining previously observed anomalous changes in electrical conductivity of the material under pressure. The crystallization of this elemental system involves local topological fluctuations and results in an unusual pressure-induced volume expansion. The metastability of the phases involved in the transition accounts for this phenomenon. The results demonstrate the use of pressure to control and directly monitor the relative densities and energetics of phases to create new phases from highly metastable states. The microtomographic technique developed here represents a method for determination of the equations of state of amorphous materials at extreme pressures and temperatures.
journal_name
Proc Natl Acad Sci U S Aauthors
Liu H,Wang L,Xiao X,De Carlo F,Feng J,Mao HK,Hemley RJdoi
10.1073/pnas.0806857105subject
Has Abstractpub_date
2008-09-09 00:00:00pages
13229-34issue
36eissn
0027-8424issn
1091-6490pii
0806857105journal_volume
105pub_type
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