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This content will become publicly available on January 10, 2019

Title: Phase transformation pathways of ultrafast-laser-irradiated Ln 2 O 3 ( Ln = Er Lu )

Ultrafast laser irradiation causes intense electronic excitations in materials, leading to transient high temperatures and pressures. Here, we show that ultrafast laser irradiation drives an irreversible cubic-to-monoclinic phase transformation in Ln 2O 3 ( Ln = Er – Lu ) , and explore the mechanism by which the phase transformation occurs. A combination of grazing incidence x-ray diffraction and transmission electron microscopy are used to determine the magnitude and depth-dependence of the phase transformation, respectively. Although all compositions undergo the same transformation, their transformation mechanisms differ. The transformation is pressure-driven for Ln = Tm – Lu , consistent with the material's phase behavior under equilibrium conditions. However, the transformation is thermally driven for Ln = Er , revealing that the nonequilibrium conditions of ultrafast laser irradiation can lead to novel transformation pathways. Ab initio molecular-dynamics simulations are used to examine the atomic-scale effects of electronic excitation, showing the production of oxygen Frenkel pairs and the migration of interstitial oxygen to tetrahedrally coordinated constitutional vacancy sites, the first step in a defect-driven phase transformation.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [1]
  1. Stanford Univ., CA (United States)
  2. Univ. of California, Berkeley, CA (United States)
  3. Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Grant/Contract Number:
SC0001089; AC02-76SF00515; AC02-05CH11231; FA9550-16-1-0312; ECCS-1542152
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 2; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1424744