TY - JOUR

T1 - Unique Nanomechanical Properties of Diamond-Lonsdaleite Biphases

T2 - Combined Experimental and Theoretical Consideration of Popigai Impact Diamonds

AU - Baek, Woohyeon

AU - Gromilov, Sergey A.

AU - Kuklin, Artem V.

AU - Kovaleva, Evgenia A.

AU - Fedorov, Alexandr S.

AU - Sukhikh, Alexander S.

AU - Hanfland, Michael

AU - Pomogaev, Vladimir A.

AU - Melchakova, Iuliia A.

AU - Avramov, Paul V.

AU - Yusenko, Kirill V.

N1 - Publisher Copyright: © 2019 American Chemical Society.

PY - 2019/3/13

Y1 - 2019/3/13

N2 - For the first time, lonsdaleite-rich impact diamonds from one of the largest Popigai impact crater (Northern Siberia) with a high concentration of structural defects are investigated under hydrostatic compression up to 25 GPa. It is found that, depending on the nature of a sample, the bulk modulus for lonsdaleite experimentally obtained by X-ray diffraction in diamond-anvil cells is systematically lower and equal to 93.3-100.5% of the average values of the bulk moduli of a diamond matrix. Density functional theory calculations reveal possible coexistence of a number of diamond/lonsdaleite and twin diamond biphases. Among the different mutual configurations, separate inclusions of one lonsdaleite (001) plane per four diamond (111) demonstrate the lowest energy per carbon atom, suggesting a favorable formation of single-layer lonsdaleite (001) fragments inserted in the diamond matrix. Calculated formation energies and experimental diamond (311) and lonsdaleite (331) powder X-ray diffraction patterns indicate that all biphases could be formed under high-temperature, high-pressure conditions. Following the equation of states, the bulk modulus of the diamond (111)/lonsdaleite (001) biphase is the largest one among all bulk moduli, including pristine diamond and lonsdaleite.

AB - For the first time, lonsdaleite-rich impact diamonds from one of the largest Popigai impact crater (Northern Siberia) with a high concentration of structural defects are investigated under hydrostatic compression up to 25 GPa. It is found that, depending on the nature of a sample, the bulk modulus for lonsdaleite experimentally obtained by X-ray diffraction in diamond-anvil cells is systematically lower and equal to 93.3-100.5% of the average values of the bulk moduli of a diamond matrix. Density functional theory calculations reveal possible coexistence of a number of diamond/lonsdaleite and twin diamond biphases. Among the different mutual configurations, separate inclusions of one lonsdaleite (001) plane per four diamond (111) demonstrate the lowest energy per carbon atom, suggesting a favorable formation of single-layer lonsdaleite (001) fragments inserted in the diamond matrix. Calculated formation energies and experimental diamond (311) and lonsdaleite (331) powder X-ray diffraction patterns indicate that all biphases could be formed under high-temperature, high-pressure conditions. Following the equation of states, the bulk modulus of the diamond (111)/lonsdaleite (001) biphase is the largest one among all bulk moduli, including pristine diamond and lonsdaleite.

KW - compressibility

KW - diamond/lonsdailete biphases

KW - high-pressure

KW - Impact diamonds

KW - lonsdaleite

UR - http://www.scopus.com/inward/record.url?scp=85061932515&partnerID=8YFLogxK

U2 - 10.1021/acs.nanolett.8b04421

DO - 10.1021/acs.nanolett.8b04421

M3 - Article

C2 - 30735045

AN - SCOPUS:85061932515

VL - 19

SP - 1570

EP - 1576

JO - Nano Letters

JF - Nano Letters

SN - 1530-6984

IS - 3

ER -