Impact of anharmonic effects on the phase stability, thermal transport, and electronic properties of AlN
Abstract
Wurtzite aluminium nitride (AlN) is a technologically important wide-band-gap semiconductor with an unusually high thermal conductivity, used in optical applications and as a heatsink substrate. Explaining many of its properties depends on an accurate description of its lattice dynamics, which have thus far only been captured in the quasiharmonic approximation. In this work, we show that anharmonic effects have a considerable impact on its phase stability and transport properties, since they are much stronger in the rocksalt phase. We construct a theoretical pressure-temperature phase diagram of AlN, demonstrating that the rocksalt phase is stabilized by increasing temperature, with respect to the wurtzite phase. We recover the thermal conductivity of the wurtzite phase (320Wm^(-1)K^(-1) under ambient conditions) and compute the hitherto unknown thermal conductivity of the rocksalt phase (81Wm^(-1)K^(-1)). We also show that the electronic band gap decreases with temperature. These findings provide further evidence that anharmonic effects cannot be ignored in simulations of materials intended for high-temperature applications.
Additional Information
© 2016 American Physical Society. Received 16 May 2016; published 26 September 2016. Support from the Swedish Research Council (VR programs 2015-04391 and 621-2012-4401), Swedish Foundation for Strategic Research (SSF program SRL10-0026), and VINNOVA [M-Era.net Project No. 2013-02355 (MC2)] is acknowledged. O.H. acknowledges the Swedish Research Council VR program 637-2013-7296. Z.R. acknowledges the Swedish Foundation for Strategic Research (SSF) program FUNCASE. I.A.A. is grateful for the support from the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST "MISIS" (No. K2-2016-013). All calculations were performed using the supercomputer resources of the SwedishNational Infrastructure for Computing (SNIC), National Supercomputer Centre at Linköping University (NSC) and the PDC Center for High Performance Computing at the KTH Royal Institute of Technology.Attached Files
Published - PhysRevB.94.104305.pdf
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Additional details
- Eprint ID
- 70641
- Resolver ID
- CaltechAUTHORS:20160928-121330323
- 2015-04391
- Swedish Research Council
- 621-2012-4401
- Swedish Research Council
- SRL10-0026
- Swedish Foundation for Strategic Research
- 2013-02355
- VINNOVA
- 637-2013-7296
- Swedish Research Council
- K2-2016-013
- Ministry of Education and Science of the Russian Federation
- Created
-
2016-09-28Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field