A Landau-Devonshire Approach of Elastic Strain Effects on Ferroelectric Al1-xScxN
Conference
·
OSTI ID:1994154
Landau-Devonshire thermodynamic modeling enables the phenomenological description of ferroelectrics. 1 The approach has been validated across a wide range of ferroelectric materials from the first ferroelectric discovered, Rochelle Salt, to recent HfO2-based materials. 2-4 Extension to what is now referred to as the Landau-Ginsburg-Devonshire model enables rigorous investigation of polarization boundaries and reorientation, phase transformations, and domain formation/evolution. We present a thermodynamic analysis of the recently discovered nitride ferroelectric materials 5-7 using the classic Landau-Devonshire approach. The electrostrictive and dielectric stiffness coefficients of Al1-xScxN with wurtzite structure (6mm) are determined using a free energy density function assuming a hexagonal parent phase (6/mmm), with the first order phase transition based on the dielectric stiffness relationships (Fig. 1). The results of this analysis show that the strain sensitivity of the energy barrier is one order of magnitude larger than that of the spontaneous polarization in these wurtzite ferroelectrics, yet both are less sensitive to strain compared to classic perovskite ferroelectrics (Fig. 2). These analysis results reported here explain experimentally reported sensitivity of coercive field to elastic strain/stress in Al1-xScxN films, and would enable further thermodynamic analysis via phase field simulation and related methods.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- U.S. Department of Defense (DOD), Defense Advanced Research Projects Agency (DARPA), Tunable Ferroelectric Nitrides (TUFEN) Program; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- AC36-08GO28308;
- OSTI ID:
- 1994154
- Report Number(s):
- NREL/PO-5K00-85256; MainId:86029; UUID:e21858cb-640f-4278-b7f7-cb759a37de0f; MainAdminID:70117
- Conference Information:
- Presented at the Fundamental Physics of Ferroelectrics Workshop, 5-8 February 2023, Golden, Colorado
- Country of Publication:
- United States
- Language:
- English
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