About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Phase Stability, Phase Transformations, and Reactive Phase Formation in Electronic Materials XXI
|
Presentation Title |
Study of Ferroelectricity and Phase Transitions in Hafnia |
Author(s) |
Sesha Sai Behara, Anton Van der Ven |
On-Site Speaker (Planned) |
Sesha Sai Behara |
Abstract Scope |
Ferroelectric materials are of considerable interest for memory and logic device applications such as ferroelectric random-access memory (FRAM), ferroelectric field-effect transistors (FeFET) and negative-capacitance field-effect transistors (NC-FET). While much effort has been devoted to ferroelectric perovskites, it is increasingly recognized that a ferroelectric orthorhombic form of HfO2 is in many ways superior. HfO2 can adopt a multitude of polymorphs depending on temperature, dopant/alloy composition, strain state, electric field and film thickness. In this work, we study the structural phase transformations between orthorhombic HfO2 and its other polymorphs from first principles. By combining density functional theory with the group theory of symmetry, we develop a generalized free energy description that is a function of shuffle order parameters, strain and dopant composition and connects all known polymorphs of HfO2. The free energy surface provides crucial insights about the coercive field, nucleation barriers for switching, coherent phase equilibrium and twin boundary migration. |
Proceedings Inclusion? |
Planned: |
Keywords |
Electronic Materials, Computational Materials Science & Engineering, Phase Transformations |