Ferroelectronics Lab

Understanding and utilizing non-volatile properties of materials

Advanced Science Showcases Work on Their Cover Page

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“Chemically-Disordered Transparent Conductive Perovskites With High Crystalline Fidelity,” a publication from July 2025 with strong contributions from Pat Keezer, gains attention this month. A graphical abstract artistically describing the work was used on the cover of volume 12, issue 42 of Advanced Science.

“A pulsed laser generates a high-energy plasma plume that quenches and kinetically arrests a high-symmetry, high-entropy, chemically disordered perovskite thin film on a substrate, yielding a material that is simultaneously conductive and transparent. This cover highlights the power of pulsed laser deposition and fast quenching to realize such phases with high crystalline fidelity.” See Advanced Science for more information.

Orignial Abstract: This manuscript presents a working model linking chemical disorder and transport properties in correlated-electron perovskites with high-entropy formulations and a framework to actively design them. This work demonstrates this new learning in epitaxial Srx(Ti,Cr,Nb,Mo,W)O3 thin films that exhibit exceptional crystalline fidelity despite a diverse chemical formulation where most B-site species are highly misfit with respect to valence and radius. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy confirm a unique combination of chemical disorder and structural perfection in thin and thick epitaxial layers. This combination produces an optical transparency window that surpasses that of the constituent end-members in the UV and IR, while maintaining relatively low electrical resistivity. This work addresses the computational challenges of modeling such systems and investigate short-range ordering using cluster expansion. These results showcase that unusual d-metal combinations access an expanded property design space that is predictable using end-member characteristics and their interactions – though unavailable to them – thus offering performance advances in optical, high-frequency, spintronic, and quantum devices.

Read more at Advanced Science

New Publication! “Signatures of quantum spin liquid state and unconventional transport in thin film TbInO3”

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Abstract: Quantum spin liquids, where the frustrated magnetic ground state hosts highly entangled spins resisting long-range order to 0 K, are exotic quantum magnets proximate to unconventional superconductivity and candidate platforms for topological quantum computing. Although several quantum spin liquid material candidates have been identified, thin films crucial for device fabrication and further tuning of properties remain elusive. Recently, hexagonal TbInO3 has emerged as a quantum spin liquid candidate which also hosts improper ferroelectricity and exotic high-temperature carrier transport. Here, we synthesize thin films of TbInO3 and characterize their magnetic and electronic properties. Our films present a highly frustrated magnetic ground state without long-range order to 0.4 K, consistent with bulk crystals. We further reveal a rich ferroelectric domain structure and unconventional non-local transport near room temperature, suggesting hexagonal TbInO3 as a promising candidate for realizing exotic magnetic and transport phenomena in epitaxial heterostructures.

Read more at Nature Communications

Tony Chiang Defends His Thesis, Earning a PhD! Congratulations Tony!

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Tony gave his defence today, 8/19/25, on the ““Polarization Evolution Behavior in
Scaled Ferroelectric Capacitors.” Here, he discussed his research which involved the development of ferroelectric capacitors down to 100 nm in lateral dimention. Using these capacitors, he explored three ferroelectric materials to identify their switching kinetics and limits. Here, he identified a circuit limited and material limited behavior regime differentiated by lateral dimention, the latter which is useful for accurately isolating materials properties. He also establishes a criteria for identifying this regime.

Congratulations Tony, great work!

New Publication! Sub-100 Ω/□ sheet resistance of GaN HEMT with ScAlN barrier

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Abstract: A low sheet resistance of 95.5 Ω/□ at room temperature has been demonstrated in an MBE-grown Sc0.15Al0.85N/AlN/GaN epitaxial HEMT structure. Owing to the strong spontaneous and piezoelectric polarization of ScAlN, a large two-dimensional electron gas density of 7.8 × 1013 cm−2 and a relatively high mobility of 836 cm2/V·s were demonstrated with a 15 nm Sc0.15Al0.85N barrier. Further investigation under low temperature on this structure reveals a reduced sheet resistance to 33.3 Ω/□ and mobility increased to 4223 cm2/V·s at 10 K. The dependence of sheet carrier density, mobility, and the associated sheet resistance on ScAlN thickness was further studied. The compelling electron transport properties demonstrated in the structure position ScAlN as a strong contender as the barrier layer in future GaN HEMT devices.

Read more at Applied Physics Letters

Intel Awards John T. Heron and lab with Outstanding Researcher Award!

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Once a year, Intel presents an award acknowledging work that makes “a significant impact on future technology” and “celebrates exceptional achievements made through Intel sponcered research.” John T. Heron is among the 10 researchers who have recieved this distinguished award.

“The research team demonstrated ultrafast switching of La-doped BiFeO3 ferroelectric capacitors, developed novel metrologies to measure polarization dynamics at nanoscale, demonstrated modeling frameworks to understand the effect of key physical processes such as domain nucleation, growth, and circuit limits on the switching process, and determined a new regime of energy-delay scaling behavior relevant for computing technologies. Furthermore, the researchers developed novel materials critical for accelerating magneto-electric spin-orbit (MESO) device development to deliver target specifications, such as high entropy perovskite oxides with large spin Hall efficiency and resistivity as well as double perovskite ferromagnet layers epitaxially compatible with La-doped BiFeO3.”

Congratulations to both John and the remainder of the research team who supported this achievement! Read more on Intel’s website if you are interested about this achievement.

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Our research is at the intersection of multiple disciplines, drawing on principles and methodologies from materials science, chemistry, physics, and electrical engineering. Our mission is to pioneer … Read More

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Ferroelectronics Lab
Address: 2030 H.H. Dow

T: (734) 763-6914
E: jtheron@umich.edu