Thermal resistance of twist boundaries in silicon nanowires by nonequilibrium molecular dynamics

JK Bohrer and K Schroer and L Brendel and DE Wolf, AIP ADVANCES, 7, 045105 (2017).

DOI: 10.1063/1.4979982

The thermal boundary resistance (Kapitza resistance) of (001) twist boundaries in silicon is investigated by nonequilibrium molecular dynamics simulations. In order to enable continuous adjustment of the mismatch angle, a cylindrical geometry with fixed atomic positions at the boundaries is devised. The influence of the boundary conditions on the Kapitza resistance is removed by means of a finite size analysis. Due to the diamond structure of silicon, twist boundaries with mismatch angles phi and 90 degrees - phi are not equivalent, whereas those with +/-phi or with 90 degrees +/- phi are. The Kapitza resistance increases with mismatch angle up to 45 degrees, where it reaches a plateau around 1.56 +/- 0.05 K m(2)/GW. Between 80 degrees and the 90 degrees Sigma 1 grain boundary it drops by about 30%. Surprisingly, lattice coincidence at other angles (Sigma 5, Sigma 13, Sigma 27, Sigma 25) has no noticable effect on the Kapitza resistance. However, there is a clear correlation between the Kapitza resistance and the width of a non-crystalline layer at the twist boundaries. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (

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