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I have a combined background in computational science and electromagnetic waves and functional materials & electronics. My current primary research interest is in high-fidelity computational algorithms for microelectronics applications. I work closely with material scientists, device designers, circuit architects and machine learning experts, to codesign workflow that benefits the development of future electronics.
Scroll down for my full publication list or visit my Google Scholar
Exascale Modeling
Exascale Modeling
As the microelectronics community continues to explore new materials and technologies, the demand for modeling tools has exceeded current capabilities. Emerging post-CMOS technologies often rely on trial-and-error development strategies due to the lack of adequate simulation tools. There is an ever-increasing need for higher-fidelity simulations via higher spatiotemporal resolution and/or improved coupling that can seamlessly incorporate new physics into algorithms for widely-used, standard models.
We address the need for enhanced modeling for more realistic devices by developing an algorithmically flexible capability that is performant on manycore/GPU-based supercomputers. The main product of this research is the ARTEMIS (Adaptive mesh Refinement Time-domain ElectrodynaMIcs Solver) package. The overall strategy couples a finite-difference time-domain (FDTD) approach for Maxwell’s equations to the Landau equations of magnetization or polarization. The algorithm is implemented in the Exascale Computing Project (ECP) software framework, AMReX, which provides effective scalability on manycore and GPU-based supercomputing architectures. The performance of the algorithm is demonstrated by the excellent scaling results on NERSC multicore and GPU systems, with a significant (59×) speedup on up to 2000+ GPUs using a node-by-node comparison.
ARTEMIS is able to effectively capture the multiphysics aspect of emerging microelectronics, with increased spatial resolutions. This allows for GPU simulations of various devices including multiferroic antennas, ferroelectric capacitors and transistors, magnetic RF devices, microwave circuits, etc.
Code Packages:
Click here for direct access to the Microelectronics project on GitHub.
Artemis : Adaptive mesh Refinement Time-domain ElectrodynaMIcs Solver couples the Maxwell's equations with classical equations that describe quantum material behavior (such as LLG equation for micromagnetics, GL equation for ferroelectrics, and London equation for superconducting materials) for quantifying the performance of next-generation microelectronics. Click here for direct access to the ARTEMIS package on GitHub.
FerroX : a massively parallel, 3D phase-field simulation framework for modeling ferroelectric materials based scalable logic devices. Click here for direct access to the FerroX package on GitHub.
MagneX : Micromagnetics module. Click here for direct access to the MagneX package on GitHub.
ELEQTRONeX : Electrostatic module for transistor analysis. Click here for direct access to the eXstatic package on GitHub.
Electromagnetics & Radio-frequency Devices
Electromagnetics & Radio-frequency Devices
Electromagnetic (EM) waves play a pivotal role in my research, forming the foundation for innovative microwave devices with significant practical impact. RF components that leverage coupled physical mechanisms, such as acoustic wave resonators and magnetically induced antennas, have emerged as critical enablers of high-performance radio frequency front-ends. These advancements pave the way for groundbreaking applications ranging from advanced radar systems to miniature implantable health-monitoring devices. EM waves drive extensive research, spanning atomic-scale wave-material interactions to system-level architecture design, across fields like advanced materials, nanotechnology, sensing, and quantum and advanced computing. By exploring multiferroic, ferroelectric, and (anti-)ferromagnetic materials, I focus on enabling low-power, high-efficiency devices. Specifically, by integrating these ferroic phases in magnetoelectric configurations, my work achieves magnetization-to-voltage conversion without the need for inductors—an essential innovation for nanoscale device integration with transformative potential.
Hybrid Quantum
Hybrid Quantum
Hybrid quantum systems offer a new paradigm of combining quantum modules and well-defined dynamic physics in the classical regime. They have found applications in coherent information processing, as the coherence of information carried in dynamic excitations can be maintained while being transduced between modules.
Related publications:
Bulk acoustic wave mediated multiferroic antennas: architecture and performance bound
Zhi Yao, Yuanxun Ethan Wang; Scott Keller; Gregory P. Carman, IEEE Transactions on Antennas and Propagation, vol. 63, pp. 3335-3344, Aug. 2015.
Enhanced planar antenna efficiency through magnetic thin-films
Zhi Yao, Sidhant Tiwari, Joseph Schneider, Robert N. Candler, Greg P. Carman, and Yuanxun Ethan Wang, IEEE Journal on Multiscale and Multiphysics Computational Techniques, 6, pp.249-258, Dec. 2021.
Modeling of multiple dynamics in the radiation of bulk acoustic wave (BAW) antennas
Zhi Yao, Sidhant Tiwari, Ting Lu, Jesse Rivera, Kevin Luong, Rob N. Candler, Greg P. Carman and Yuanxun Ethan Wang, IEEE Journal on Multiscale and Multiphysics Computational Techniques, vol. 5, pp. 7-20, Dec. 2019.
Rui-Fu Xu, Louis-Charles Ippet-Letembet, Sidhant Tiwari, Zhi Yao, Shih-Ming Huang, Rob N Candler, Shih-Yuan Chen, Applied Physics Letters 123, no. 16, 2023.
Beyond Moore's Law
Beyond Moore's Law
As Moore’s Law first predicted in 1975, CMOS silicon chips are approaching limits in miniaturization and performance. It is critical to explore new physical phenomena that will lead to significantly higher energy efficiency in microelectronics. Ferroelectric, spintronic, and multiferroic materials have become leading contenders for future electronics. Orders of magnitude improvement in energy efficiency are possible by exploiting correlations (electronic charge/spin and dipolar). Thus, we aim to design and manipulate this energy barrier to specifically reduce the operating voltage substantially below what is achievable by today's CMOS technology.
Ferroelectric materials have enabled a wide portfolio of innovative microelectronics devices due to their switchable polarization in response to applied electric fields. The remnant polarization in the ferroelectric material at zero applied electric field allows for nonvolatile retention in these devices. The unique physics of ferroelectric field effect transistors (FeFETs) has been instrumental in the design of other new technologies including nonvolatile memories, logic-in-memory (LiM) architectures, oscillators and negative capacitance field effect transistors (NCFETs). We have built a massively parallel, 3D phase-field simulation framework for modeling ferroelectric materials-based scalable logic devices. The charge (Q) v.s. voltage (V) responses for these 3D structures clearly indicate stabilized negative capacitance with multidomain formation, which is corroborated by amplification of the voltage at the interface between the ferroelectric and dielectric layers.
Spintronics has emerged as one of the leading options for low-energy computing due to an intriguing combination of non-volatility, higher logic efficiency, and the potential for logic-in-memory function. Spintronics aims to enhance and replace standard charge-based electronics by harnessing the electron’s spin. Materials that have more than one ferroic ordering at the same time are known as ‘multiferroics’. In particular, strong magnetoelectric (ME) coupling in multiferroic materials could enable ultra-low voltage switching to convert charge to spin via ME actuation at <100 mV. We are actively developing highly efficient logic-in-memory operations with robustly switched spins by electric fields.
Related publications:
3D ferroelectric phase field simulations of polycrystalline multi-phase hafnia and zirconia based ultra-thin films
P. Kumar*, M. Hoffmann, A. Nonaka, S. Salahuddin, Z. Yao*, Advanced Electronic Materials (2024): 2400085.
FerroX: A GPU-accelerated, 3D phase-field simulation framework for modeling ferroelectric devices
Prabhat Kumar, Andy Nonaka, Revathi Jambunathan, Girish Pahwa, Sayeef Salahuddin, and Zhi Yao, Computer Physics Communications 290 (2023): 108757.
Designed spin-texture-lattice to control anisotropic magnon transport in antiferromagnets
Peter Meisenheimer, et al., Advanced Materials, 2024, 2404639.
Manipulating chiral-spin transport with ferroelectric polarization
Xiaoxi Huang, et al., Nature Materials 23, 898–904 (2024).
Low-temperature grapho-epitaxial La-substituted BiFeO3 on a metallic perovskite
Sajid Husain, et al., Nature Communications, 15, 479, 2024.
Full Publication List:
Full Publication List:
Symmetry-based phenomenological model for magnon transport in a multiferroic
I.A. Harris, S. Husain, P. Meisenheimer, M. Ramesh, H.W. Park, L. Caretta, D. Schlom, Z. Yao, L.W. Martin, J. ´I˜niguez-Gonz´alez, S.K. Kim, and R. Ramesh, accepted by Physical Review Letters, 2024. arXiv preprint arXiv:2411.10903. [doi]Optical neural engine for solving scientific partial differential equations
Y. Tang, R. Chen, M. Lou, J. Fan, C. Yu, A. Nonaka, Z. Yao* and W. Gao, under review, 2024. arXiv preprint arXiv:2409.06234. [doi]ELEQTRONeX: A GPU-Accelerated exascale framework for non-equilibrium quantum transport in nanomaterials
S. S. Sawant, F. Leonard, Z. Yao, A. Nonaka, accepted by npj Computational Materials, arXiv:2407.14633. [doi]Mechanical antenna simulations via FDTD to characterize mutual depolarization
J. Rivera, J. Blaske, Z. Yao, R. Zheng, G. P. Carman and Y. E. Wang, IEEE Journal on Multiscale and Multiphysics Computational Techniques, vol. 10, pp. 8-27, 2024. [doi]
Modeling of multiferroic antennas in the Akhiezer regime: effects of acoustic resonator excitation and topology on radiation
L. -C. Ippet-Letembet, R. -F. Xu, R. Jeanty, Z. Yao, R. N. Candler and S. -Y. Chen, IEEE Transactions on Antennas and Propagation, vol. 1, pp. 1, 2024. [doi]Roadmap on low-power electronics
R. Ramesh, S. Salahuddin, S. Datta, C. H. Diaz, D. E. Nikonov, I. A. Young, D. Ham, et al., Applied Physics Letters, 12, 099201 (2024), all authors contribute equally, 2024. [doi]Non-volatile magnon transport in a single domain multiferroic
S. Husain*, I. Harris, P. Meisenheimer, S. Mantri, X. Li, M. Ramesh, P. Behera, H. Taghinejad, J. Kim, and P. Kavle, S. Zhou, T.Y. Kim, H. Zhang, P. Stevenson, J. G. Analytis, D. Schlom, S. Salahuddin, J. ´I˜niguez-Gonz´alez, B. Xu, L. W. Martin, L. Caretta, Y. Han, L. Bellaiche, Z. Yao* and R. Ramesh*, Nature Communications, 15, 5966, 2024. [doi]3D ferroelectric phase field simulations of polycrystalline multi-phase hafnia and zirconia based ultra-thin films
P. Kumar*, M. Hoffmann, A. Nonaka, S. Salahuddin, Z. Yao*, Advanced Electronic Materials (2024): 2400085. [doi]Manipulating chiral-spin transport with ferroelectric polarization
X. Huang, X. Chen, Y. Li, J. Mangeri, H. Zhang, M. Ramesh, H. Taghinejad, P. Meisenheimer, L. Caretta, S. Susarla, R. Jain, C. Klewe, T. Wang, R. Chen, C.-H. Hsu, I. Harris, S. Husain, H. Pan, J. Yin, P. Shafer, Z. Qiu, D. R. Rodrigues, O. Heinonen, D. Vasudevan, J.Iniguez- Gonzalez, D. G. Schlom, S. Salahuddin, L. W. Martin, J. G. Analytis, D. C. Ralph, R. Cheng, Z. Yao, and R. Ramesh, Nature Materials 23, 898–904 (2024). [doi]Designed Spin-Texture-Lattice to Control Anisotropic Magnon Transport in Antiferromagnets
P. Meisenheimer, M. Ramesh, S. Husain, I. Harris, H.W. Park, S. Zhou, H. Taghinejad, H. Zhang, L. W. Martin, J. Analytis, P. Stevenson, J. Iniguez-Gonzalez, S. K. Kim, D. G. Schlom, L. Caretta, Z. Yao, R. Ramesh, Advanced Materials, 2024, 2404639. [doi]Low-temperature grapho-epitaxial La-substituted BiFeO3 on a metallic perovskite
S. Husain, I. Harris, G. Gao, X. Li, P. Meisenheimer, C. Shi, P. Kavle, C. H. Choi, T. Y. Kim, D. Kang, P. Behera, D. Perrodin, H. Guo, J. M. Tour, Y. Han, L. W. Martin, Z. Yao, R. Ramesh, Nature Communications, 15, 479, 2024. [doi]Experimental validation of multiferroic antennas in GHz frequency range
R.F. Xu, L.C. Ippet-Letembet, S. Tiwari, Z. Yao, S.M. Huang, R. N. Candler, S.Y. Chen, Applied Physics Letters, 123 (16): 162902, Oct 2023. [doi]FerroX: A GPU-accelerated, 3D phase-field simulation framework for modeling ferroelectric devices
P. Kumar, A. Nonaka, R. Jambunathan, G. Pahwa, and S. Salahuddin, Z. Yao, Computer Physics Communications, 290, p.108757, 2023. [doi]Two-fluid physical modeling of superconducting resonators in the ARTEMIS framework
R. Jambunathan, Z. Yao, R. Lombardini, A. Rodriguez, and A. Nonaka. Computer Physics Communications, 108836, 2023. [doi]A massively parallel time-domain coupled electrodynamics-micromagnetics solver
Z. Yao, R. Jambunathan, Y. Zeng and A. Nonaka, International Journal of High Performance Computing Applications (IJHPCA), 36(2), pp.167-181, Jan. 2022. [doi]Characterization of transmission lines in microelectronics circuits using the ARTEMIS solver
S. Sawant, Z. Yao, R. Jambunathan, and A. Nonaka, IEEE Journal on Multiscale and Multi- physics Computational Techniques, vol. 8, pp. 31-39, 2022. [doi]Radio frequency precession modulation-based magnetic field sensors
K.Q.T. Luong, W. Gu, F. Fereidoony, L. Yeung, Z. Yao, and Y. E. Wang, IEEE Access, vol. 10, pp. 3756-3765, Jan. 2022. [doi]Enhanced planar antenna efficiency through magnetic thin-Films
Z. Yao, S. Tiwari, J. Schneider, R. N. Candler, G. P. Carman, and Y. E. Wang, IEEE Journal on Multiscale and Multiphysics Computational Techniques, vol. 6, pp. 249-258, 2021. [doi]Verification testing of multi-dynamical solver for multiferroic antennas
J. Rivera, Z. Yao, D. L. Tran, M. Y. St Cyr, R. Henderson, Y. E. Wang, and G. P. Carman, Proceedings of 2021 International Applied Computational Electromagnetics Society Symposium (ACES), pp. 1-4, Sep. 2021. [link]Towards automated superconducting circuit calibration using deep reinforcement learning
M. G. Bautista, Z. Yao, A. Butko, M. Kiran and M. Metcalf, Proceedings of 2021 IEEE Com- puter Society Annual Symposium on VLSI (ISVLSI), pp. 462-467, Jul. 2021. [doi]Ferromagnetic resonance enhanced electrically small antennas
W. Gu, K. Luong, Z. Yao, H. Cui and Y. E. Wang, IEEE Transactions on Antennas and Propagation, 69(12), pp.8304-8314, Jun. 2021. [doi]Lamb wave resonator loaded non-reciprocal RF devices
T. Lu, J. D. Schneider, X. Zou, S. Tiwari, Z. Yao, G.P. Carman, R. N. Candler, Y. E. Wang, Proceedings of IEEE/Microwave Theory and Techniques Society (MTT-S) International Mi- crowave Symposium (IMS), pp. 516-519, Aug. 2020. [doi]Underlayer effect on the soft magnetic, high frequency, and magnetostrictive properties of FeGa thin films
A. Acosta, K. Fitzell, J. D. Schneider, C. Dong, Z. Yao, R. Sheil, Y. E. Wang, G. P. Carman, N. X. Sun, and J. P. Chang, Journal of Applied Physics, 128, 013903, Jul. 2020. [doi]Enhancing the soft magnetic properties of FeGa with a non-magnetic underlayer for microwave applications
A. Acosta, K. Fitzell, J. D. Schneider, C. Dong, Z. Yao, Y. E. Wang, G. P. Carman, N. X. Sun, and J. P. Chang, Applied Physics Letters, 116, 222404, Jun. 2020. [doi]Modeling of multiple dynamics in the radiation of bulk acoustic wave (BAW) antennas
Z. Yao, S. Tiwari, T. Lu, J. Rivera, K. Luong, R. N. Candler, G. P. Carman and Y. E. Wang, IEEE Journal on Multiscale and Multiphysics Computational Techniques, vol. 5, pp. 7-20, Dec. 2019. [doi]Experimental demonstration and operating principles of a multiferroic antenna
J. D. Schneider, J. P. Domann, M. K. Panduranga, S. Tiwari, P. Shirazi, Z. Yao, et al., Journal of Applied Physics, vol. 126, 224104, Dec. 2019. [doi]3D multiscale unconditionally stable time-domain modeling of nonlinear RF thin film magnetic devices
Z. Yao, H. Cui, R. U. Tok and Y. E. Wang, Proceedings of IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, pp. 1059-1060, Jul. 2019. [doi]Coupling electromagnetic waves to spin waves: a physics-based nonlinear circuit model for frequency-selective limiters
H. Cui, Z. Yao and Y. E. Wang, IEEE Transactions on Microwave Theory and Techniques, vol. 67, pp. 3221-3229, Jun. 2019. [doi]Nonlinear surface acoustic wave grating for parametric amplification
T. Lu, J. D. Schneider, Z. Yao, G. Carman and Y. E. Wang, Proceedings of IEEE Radio and Wireless Symposium (RWS), pp. 1-3, 2019. [doi]Nonlinear equivalent-circuit model for thin-film magnetic material based RF devices
H. Cui, Z. Yao, C. Tao, Y. E. Wang, Proceedings of IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF&THz Applications (IMWS- AMP), pp. 1-3, Jul. 2018. [doi]Multiphysics time-domain modeling of nonlinear permeability in thin-film magnetic material Z. Yao, H. Cui, T. Itoh, and Y. E. Wang, Proceedings of IEEE International Microwave Sym- posium (IMS), pp. 208-211, Jun. 2018. [doi]
A multiscale, unconditionally stable time-domain (MUST) solver unifying electrodynamics and micromagnetics
Z. Yao, R. U. Tok, T. Itoh and Y. E. Wang, IEEE Transactions on Microwave Theory and Techniques, vol. 66, pp (99): 1-14, May 2018. [doi]3D modeling of BAW-based multiferroic antennas
Z. Yao and Y. E. Wang, Proceedings of IEEE International Symposium on Antennas and Propagation. & USNC/URSI National Radio Science Meeting (APS/URSI), pp. 1125-1126, Jul. 2017. [doi]3D unconditionally stable FDTD modeling of micromagnetics and electrodynamics
(Best Student Paper) Z. Yao and Y. E. Wang, “,” Proceedings of IEEE International Mi- crowave Symposium (IMS), pp. 12-15. Jun. 2017. [doi]3D ADI-FDTD modeling of platform reduction with thin film ferromagnetic material
Z. Yao and Y. E. Wang, Proceedings of IEEE International Symposium on Antennas and Propagation (APS)/URSI, pp. 2019-2020, Jun. 2016. [doi]Bulk acoustic wave mediated multiferroic antennas: architecture and performance bound
Z. Yao, Y. E. Wang, et al., “,” IEEE Transactions on Antennas and Propagation, vol. 63, pp. 3335-3344, Aug. 2015. [doi]Bulk acoustic wave mediated multiferroic antennas near ferromagnetic resonance
Z. Yao and Y. E. Wang, Proceedings of IEEE International Symposium on Antennas and Propagation (APS)/URSI, pp. 1832-1833, Jul. 2015. [doi]FDTD analysis of platform effect reduction with thin film ferrite
Z. Yao, Q. Xu and Y. E. Wang, “,” Proceedings of IEEE Radio and Wireless Symposium, pp. 59-61, Jan. 2015. [doi]Dynamic analysis of acoustic wave mediated multiferroic radiation via FDTD methods
Z. Yao and Y. E. Wang, Proceedings of IEEE International Symposium on Antennas and Propagation(APS)/URSI, pp. 731-732, Jul. 2014. [doi]
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