Ab-initio and Two-layer Graph Atomic Cluster Expansion (GRACE-2L) Foundational Machine Learning Interatomic Potential Modeling of Wurtzite AlScN and AlBN Piezoelectric Systems for Predicting their Temperature-dependent Electronic Properties in Thin Film Bulk Acoustic Wave Devices
I. P. Koutsaroff (1) ,* , C. Moe (1b), Dae Ho Kim (1), K. Cheema(1), and Garrett M. Tow (2)
1. Akoustis Technologies Corp., 858 FM 1209 Bastrop, TX 78602 USA
1b Akoustis Technologies Corp., 5450 Campus Drive, Canandaigua, NY 14424 USA
2. Materials Design Inc., 12121 Scripps Summit Drive, Suite 160, San Diego, CA 92131 USA
*Corresponding Author: ikoutsaroff@akoustis.com
In the present study, we adopt a comprehensive approach of ab-initio simulations by using a commercial software package VASP 6.5.1 based on Density Functional Theory (DFT) using a projector augmented wave (PAW) method with generalized gradient approximation (GGA) along with Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional and calculations are performed on a grid of points in real space, which allowed us to calculate the full set of piezoelectric and mechanical (acoustic) properties of Al1−xScxN (0≤x≤0.5, AlScN) and Al1−xBxN (0≤x≤0.5, AlBN) at 0K, as well as from 200K to 400K [1, 2]. The measured phase velocities and piezoelectric coupling coefficients, kt2 from Al1−xScxN (0.31≤x≤0.38, AlScN) based Thin Film Bulk Acoustic Wave Devices at 5-7 GHz allowed good consistency when comparing with ab-initio simulated piezoelectric and stiffness tensors. Two-layer Graph Atomic Cluster Expansion (GRACE-2L) foundational Machine Learning Interatomic Potential trained on the Meta Open Materials 2024 (OMat24) dataset, was utilized in predicting e33, k2, C33 and lattice densities from 200K to 400K temperature range for Al1−xBxN (0≤x≤0.5, AlBN).
References
[1] O. Ambacher, et al., Wurtzite ScAlN, InAlN, and GaAlN crystals, a comparison of structural, elastic, dielectric, and piezoelectric properties, J. Appl. Phys. 28 July 2021; 130 (4): 045102 https://doi.org/10.1063/5.0048647.
[2] I.P., Koutsaroff, et al., High Accuracy Elastic and Piezoelectric Properties Predictions of Al1−xScxN Materials and their Experimental Validation from Microacoustic Resonators within 2.7-5.1 GHz range, Joint ISAF-ICE-EMF-IWPM-PFM Meeting (ISAF 2019) July 14-19, 2019, Lausanne, Switzerland.
[3] I.P., Koutsaroff, et al., Ab-initio Modeling of Wurtzite AIBScN and Characterization of AIBScN Piezoelectric thin Film Surface Acoustic Wave Devices Covering 4-8 GHz, The Materials Design MedeA User Group Meeting (UGM 2025), October 6-8, 2025, Vienna, Austria.
Principal Materials Development Engineer
Dr. Ivoyl Koutsaroff is the Principal Materials Development Engineer at Advanced Device Engineering & Technology Development Department at Akoustis Technologies Inc., since 2022. Akoustis is presently a wholly owned subsidiary of Space Exploration Technologies Corp. (SpaceX).
Prior to that he was a Technology Foundry Program Manager at Knowles Corporation (Japan operations) working on MEMS microphone NPI and R&D. During 2016-2021 period he was with Qualcomm (Principal Engineer), and with Wisol Japan (Executive Director) focusing his efforts on high accuracy ab-initio simulations and experimental validation of high Sc-AlScN (x~30-40at% Sc) based SMR-BAW/FBAR resonators and filters targeting improvement of microacoustic device performances by lowering their viscoelastic attenuation as well as prediction and searching for new piezoelectric materials to deliver improved compare to AlScN baseline high performance RF filter components.
Since 2005, for a decade, he was working as a Principal Research Engineer at New Technology Center, Murata Manufacturing Co., Ltd., Kyoto, Japan, responsible for Ferroelectric thin film research, new functional oxides (oxynitrdes for ferroelectric and paraelectric applications) and electrode materials development, process integration and performance improvement of various RF front-end devices (e.g., BST varactors and piezo-MEMS based on non-PZT materials). He was core member of a national join collaborative project supported by the Japan Society for the Promotion of Science (JSPS) for development of tunable SAW filters. From 1998 to 2005 he has been engaged in manufacturing and development activities at Gennum Corporation (acquired by Semtech Corp. and ON Semiconductor) in Ontario, Canada, where he was a Senior Technology Development Engineer, involved with development of low dielectric loss high density ferroelectric thin film decoupling and tunablecapacitors (varactors) devices used in RF-front-end communication modules and hearing aids applications. Dr. Koutsaroff was a licensed Professional Engineer (P.Eng) in Ontario, Canada.
In 2010 he received Murata Manufacturing’s Vice-President Special Technology Development and Innovation Award for the first industrial scalable fabrication of oxynitride perovskite dielectric thin films with enhanced performances. Dr. Koutsaroff founded and organized the First International Symposium on “Advances and Enhanced Functionalities of Anion-controlled New Inorganic Materials (ANIM1)”, as part of E-MRS 2013 Spring Meeting which was held in France, May 27-31, 2013. The ANIM Symposia tradition is continuing and in 2025 the 5th ANIM Symposium was held also in France. He was the lead Guest-Editor of the Special Issue on ANIM materials of the ACS Journal of Crystal Growth&Design (2013-2014).
Ivoyl Koutsaroff is an inventor of 65 patents, has authored of about 80 research articles with h-index of 13(i10-index of 17) with more than 500 citations.
Selected Bibliography
1. I. P. Koutsaroff, et al., High Accuracy Elastic and Piezoelectric Properties Predictions of Al1−xScxN Materials and their Experimental Validation from Microacoustic Resonators within 2.7-5.1 GHz range, Joint ISAF-ICE-EMF-IWPM-PFM Meeting (ISAF 2019) July 14-19, 2019, Lausanne, Switzerland (invited talk).
2. I. P. Koutsaroff and T. Metzger, High Accuracy Elastic and Piezoelectric Properties Predictions of Al1−xScxN Materials and their Experimental Validation from Microacoustic Resonators above 2GHz range, International Conference on Nanotechnology and Nanoscience, Osaka, Japan September 2018 (Keynote Talk).
3. A. David, I.P. Koutsaroff, et al., High-Throughput Synthesis and Characterization of (BaxSr1–x)1+yTi1–yO3−δ and (BaxSr1–x)1+yTi1–yO3–zNz Perovskite Thin Films, Crystal Growth & Design 2014, 14, 2, 523-532, DOI: 10.1021/cg401259r
4. 隼瀬 幸浩, 掘露 伊保龍 [Koutsaroff], 猪口 真志, 檜貝 信一,窒化酸化物ペロブスカイトの PDF 解析, Yukihiro Hayase, Ivoyl P. Koutsaroff, Masashi Inoguchi, Shin'ichi Higai, PDF Analysis of Oxynitride Perovskites, DOI: 10.18957/rr.1.3.94 SPring-8/SACLA 利用研究成果集 DOI：10.18957/rr.1.3.94
5. I.P. Koutsaroff and Amparo Fuertes, Preface, Anion-Controlled New Inorganic Materials, Crystal Growth & Design Virtual Issue,
American Chemical Society (ACS), https://pubs.acs.org/page/cgdefu/vi/13.html
6. I.P. Koutsaroff and Hontgas, C. H., Piezoelectric material and piezoelectric device,WO2020127294A1, 2020