Nanotwinned Boron Suboxide (B6O): New Ground State of B6O

Qi An; K. Madhav Reddy; Huafeng Dong; Ming Wei Chen; Artem R. Oganov; William A. Goddard

doi:10.1021/acs.nanolett.6b01204

Nanotwinned Boron Suboxide (B₆O): New Ground State of B₆O

Qi An
, K. Madhav Reddy
, Huafeng Dong
, Ming Wei Chen
, Artem R. Oganov
, William A. Goddard

California Institute of Technology
Tohoku University
Stony Brook University
Skolkovo Institute of Science and Technology
Moscow Institute of Physics and Technology
Northwestern Polytechnical University

Research output: Contribution to journal › Article › peer-review

Abstract

Nanotwinned structures in superhard ceramics rhombohedral boron suboxide (R-B₆O) have been examined using a combination of transmission electron microscopy (TEM) and quantum mechanics (QM). QM predicts negative relative energies to R-B₆O for various twinned R-B₆O (denoted as -B₆O, 2-B₆O, and 4-B₆O), consistent with the recently predicted B₆O structure with Cmcm space group (-B₆O) which has an energy 1.1 meV/B₆O lower than R-B₆O. We report here TEM observations of this -B₆O structure, confirming the QM predictions. QM studies under pure shear deformation and indentation conditions are used to determine the deformation mechanisms of the new -B₆O phase which are compared to R-B₆O and 2-B₆O. The lowest stress slip system of -B₆O is (010)/«001» which transforms -B₆O to R-B₆O under pure shear deformation. However, under indentation conditions, the lowest stress slip system changes to (001)/«110», leading to icosahedra disintegration and hence amorphous band formation.

Original language	English
Pages (from-to)	4236-4242
Number of pages	7
Journal	Nano Letters
Volume	16
Issue number	7
DOIs	https://doi.org/10.1021/acs.nanolett.6b01204
Publication status	Published - 13 Jul 2016
Externally published	Yes

Keywords

DFT
Superhard ceramics
deformation mechanism
stacking faults energy

Access to Document

10.1021/acs.nanolett.6b01204

Cite this

@article{0adde5ef9f134744b3c17ed646a6a2d0,

title = "Nanotwinned Boron Suboxide (B6O): New Ground State of B6O",

abstract = "Nanotwinned structures in superhard ceramics rhombohedral boron suboxide (R-B6O) have been examined using a combination of transmission electron microscopy (TEM) and quantum mechanics (QM). QM predicts negative relative energies to R-B6O for various twinned R-B6O (denoted as -B6O, 2-B6O, and 4-B6O), consistent with the recently predicted B6O structure with Cmcm space group (-B6O) which has an energy 1.1 meV/B6O lower than R-B6O. We report here TEM observations of this -B6O structure, confirming the QM predictions. QM studies under pure shear deformation and indentation conditions are used to determine the deformation mechanisms of the new -B6O phase which are compared to R-B6O and 2-B6O. The lowest stress slip system of -B6O is (010)/«001» which transforms -B6O to R-B6O under pure shear deformation. However, under indentation conditions, the lowest stress slip system changes to (001)/«110», leading to icosahedra disintegration and hence amorphous band formation.",

keywords = "DFT, Superhard ceramics, deformation mechanism, stacking faults energy",

author = "Qi An and Reddy, \{K. Madhav\} and Huafeng Dong and Chen, \{Ming Wei\} and Oganov, \{Artem R.\} and Goddard, \{William A.\}",

note = "Publisher Copyright: {\textcopyright} 2016 American Chemical Society.",

year = "2016",

month = jul,

day = "13",

doi = "10.1021/acs.nanolett.6b01204",

language = "English",

volume = "16",

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TY - JOUR

T1 - Nanotwinned Boron Suboxide (B6O)

T2 - New Ground State of B6O

AU - An, Qi

AU - Reddy, K. Madhav

AU - Dong, Huafeng

AU - Chen, Ming Wei

AU - Oganov, Artem R.

AU - Goddard, William A.

PY - 2016/7/13

Y1 - 2016/7/13

N2 - Nanotwinned structures in superhard ceramics rhombohedral boron suboxide (R-B6O) have been examined using a combination of transmission electron microscopy (TEM) and quantum mechanics (QM). QM predicts negative relative energies to R-B6O for various twinned R-B6O (denoted as -B6O, 2-B6O, and 4-B6O), consistent with the recently predicted B6O structure with Cmcm space group (-B6O) which has an energy 1.1 meV/B6O lower than R-B6O. We report here TEM observations of this -B6O structure, confirming the QM predictions. QM studies under pure shear deformation and indentation conditions are used to determine the deformation mechanisms of the new -B6O phase which are compared to R-B6O and 2-B6O. The lowest stress slip system of -B6O is (010)/«001» which transforms -B6O to R-B6O under pure shear deformation. However, under indentation conditions, the lowest stress slip system changes to (001)/«110», leading to icosahedra disintegration and hence amorphous band formation.

AB - Nanotwinned structures in superhard ceramics rhombohedral boron suboxide (R-B6O) have been examined using a combination of transmission electron microscopy (TEM) and quantum mechanics (QM). QM predicts negative relative energies to R-B6O for various twinned R-B6O (denoted as -B6O, 2-B6O, and 4-B6O), consistent with the recently predicted B6O structure with Cmcm space group (-B6O) which has an energy 1.1 meV/B6O lower than R-B6O. We report here TEM observations of this -B6O structure, confirming the QM predictions. QM studies under pure shear deformation and indentation conditions are used to determine the deformation mechanisms of the new -B6O phase which are compared to R-B6O and 2-B6O. The lowest stress slip system of -B6O is (010)/«001» which transforms -B6O to R-B6O under pure shear deformation. However, under indentation conditions, the lowest stress slip system changes to (001)/«110», leading to icosahedra disintegration and hence amorphous band formation.

KW - DFT

KW - Superhard ceramics

KW - deformation mechanism

KW - stacking faults energy

U2 - 10.1021/acs.nanolett.6b01204

DO - 10.1021/acs.nanolett.6b01204

M3 - Article

AN - SCOPUS:84978674756

SN - 1530-6984

VL - 16

SP - 4236

EP - 4242

JO - Nano Letters

JF - Nano Letters

IS - 7