TY - JOUR
T1 - Ultrafast formation of a transient two-dimensional diamondlike structure in twisted bilayer graphene
AU - Luo, Duan
AU - Hui, Dandan
AU - Wen, Bin
AU - Li, Renkai
AU - Yang, Jie
AU - Shen, Xiaozhe
AU - Reid, Alexander Hume
AU - Weathersby, Stephen
AU - Kozina, Michael E.
AU - Park, Suji
AU - Ren, Yang
AU - Loeffler, Troy D.
AU - Sankaranarayanan, S. K.R.S.
AU - Chan, Maria K.Y.
AU - Wang, Xing
AU - Tian, Jinshou
AU - Arslan, Ilke
AU - Wang, Xijie
AU - Rajh, Tijana
AU - Wen, Jianguo
N1 - Funding Information:
We thank Dr. J. A. Jaszczak for providing single-crystal bulk graphite samples, Dr. M. Harb and Dr. M. Mo for helpful discussion, and S. Yu for assistance in MD simulations. D.L. thanks the China Scholarships Council (CSC) Joint PhD Training Program for the financial support of studying abroad. This work was performed at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and supported by the US Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The MeV-UED experiments were carried out at SLAC MeV-UED, U.S. Department of Energy Office of Science User Facilities, operated as part of the Linac Coherent Light Source at the SLAC National Accelerator Laboratory, supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. This work was also supported by the National Natural Science Foundation of China (NSFC, Grants No. 51925105, No. 51771165, and No. 11805267), and the National Key R&D Program of China (Grant No. YS2018YFA070119).
Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/10/29
Y1 - 2020/10/29
N2 - Due to the absence of matching carbon atoms at honeycomb centers with carbon atoms in adjacent graphene sheets, theorists predicted that a sliding process is needed to form AA, AB′, or ABC stacking when directly converting graphite into sp3 bonded diamond. Here, using twisted bilayer graphene, which naturally provides AA and AB′ stacking configurations, we report the ultrafast formation of a transient two-dimensional diamondlike structure (which is not observed in aligned graphene) under femtosecond laser irradiation. This photoinduced phase transition is evidenced by the appearance of bond lengths of 1.94 and 3.14 Å in the time-dependent differential pair distribution function using MeV ultrafast electron diffraction. Molecular dynamics and first-principles calculation indicate that sp3 bonds nucleate at AA and AB′ stacked areas in a moiré pattern. This work sheds light on the direct graphite-to-diamond transformation mechanism, which has not been fully understood for more than 60 years.
AB - Due to the absence of matching carbon atoms at honeycomb centers with carbon atoms in adjacent graphene sheets, theorists predicted that a sliding process is needed to form AA, AB′, or ABC stacking when directly converting graphite into sp3 bonded diamond. Here, using twisted bilayer graphene, which naturally provides AA and AB′ stacking configurations, we report the ultrafast formation of a transient two-dimensional diamondlike structure (which is not observed in aligned graphene) under femtosecond laser irradiation. This photoinduced phase transition is evidenced by the appearance of bond lengths of 1.94 and 3.14 Å in the time-dependent differential pair distribution function using MeV ultrafast electron diffraction. Molecular dynamics and first-principles calculation indicate that sp3 bonds nucleate at AA and AB′ stacked areas in a moiré pattern. This work sheds light on the direct graphite-to-diamond transformation mechanism, which has not been fully understood for more than 60 years.
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U2 - 10.1103/PhysRevB.102.155431
DO - 10.1103/PhysRevB.102.155431
M3 - Article
AN - SCOPUS:85095564590
SN - 0163-1829
VL - 102
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
IS - 15
M1 - 155431
ER -