A Landau–Devonshire analysis of strain effects on ferroelectric Al1−xScxN
Abstract
We present a thermodynamic analysis of the recently discovered nitride ferroelectric materials using the classic Landau–Devonshire approach. Electrostrictive and dielectric stiffness coefficients of Al1−xScxN with a wurtzite structure (6 mm) 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. 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. These analysis results reported here explain experimentally reported sensitivity of the coercive field to elastic strain/stress in Al1−xScxN films and would enable further thermodynamic analysis via phase field simulation and related methods.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 25, 2022
- Source ID
- 10.1063/5.0098979
Entities
People
- Andriy Zakutayev
- Geoff L. Brennecka
- Keisuke Yazawa
Organizations
- Colorado School of Mines
- Defense Advanced Research Projects Agency
- National Science Foundation
- Office of Science