Ferroelectronics Lab

Understanding and utilizing non-volatile properties of materials

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Nguyen defends her PhD dissertation! Congratulations Nguyen!

August 11, 2021 By Matt Webb

Today, Nguyen gave a great defense of her PhD dissertation, titled “Strain engineering of perpendicular magnetic insulators for magnetoelectronics“. Congratulations Nguyen! The Ferroelectronics Lab wishes you the very best luck in your future work!

Filed Under: Graduate Student Progress

New Publication! “Toward the predictive discovery of ambipolarly dopable ultra-wide-band-gap semiconductors: The case of rutile GeO2”

July 1, 2021 By Matt Webb

ABSTRACT

Ultrawide-band-gap (UWBG) semiconductors are promising for fast, compact, and energy-efficient power-electronics devices. Their wider band gaps result in higher breakdown electric fields that enable high-power switching with a lower energy loss. Yet, the leading UWBG semiconductors suffer from intrinsic materials’ limitations with regard to their doping asymmetry that impedes their adoption in CMOS technology. Improvements in the ambipolar doping of UWBG materials will enable a wider range of applications in power electronics as well as deep-UV optoelectronics. These advances can be accomplished through theoretical insights on the limitations of current UWBG materials coupled with the computational prediction and experimental demonstration of alternative UWBG semiconductor materials with improved doping and transport properties. As an example, we discuss the case of rutile GeO2 (r-GeO2), a water-insoluble GeO2 polytype, which is theoretically predicted to combine an ultra-wide gap with ambipolar dopability, high carrier mobilities, and a higher thermal conductivity than β-Ga2O3. The subsequent realization of single-crystalline r-GeO2 thin films by molecular beam epitaxy provides the opportunity to realize r-GeO2 for electronic applications. Future efforts toward the predictive discovery and design of new UWBG semiconductors include advances in first-principles theory and high-performance computing software, as well as the demonstration of controlled doping in high-quality thin films with lower dislocation densities and optimized film properties.

Full text available from Applied Physics Letters 

Filed Under: Publications

New Publication! Fully epitaxial ferroelectric ScAlN grown by molecular beam epitaxy

June 3, 2021 By Matt Webb

We report on the demonstration of ferroelectricity in ScxAl1-xN grown by molecular beam epitaxy on GaN templates. Distinct polarization switching is unambiguously observed for ScxAl1-xN films with Sc contents in the range of 0.14–0.36. Sc0.20Al0.80N, which is nearly lattice- matched with GaN, exhibiting a coercive field of ~ 4.2 MV/cm at 10 kHz and a remnant polarization of ~ 135 uC/cm2. After electrical poling, Sc0.20Al0.80N presents a polarization retention time beyond 105 s. No obvious fatigue behavior can be found with up to 3 x 105 switching cycles. The work reported here is more than a technical achievement. The realization of ferroelectric single-crystalline III–V semiconductors by molecular beam epitaxy promises a thickness scaling into the nanometer regime and makes it possible to integrate high-performance fer- roelectric functionality with well-established semiconductor platforms for a broad range of electronic, optoelectronic, and photonic device applications.

Full text available from Applied Physics Letters

Filed Under: Publications

New Publication! Engineering new limits to magnetostriction through metastability in iron-gallium alloys

May 17, 2021 By Matt Webb

Magnetostrictive materials transduce magnetic and mechanical energies and when combined with piezoelectric elements, evoke magnetoelectric transduction for high-sensitivity magnetic field sensors and energy-efficient beyond-CMOS technologies. The dearth of ductile, rare- earth-free materials with high magnetostrictive coefficients motivates the discovery of superior materials. Fe1−xGax alloys are amongst the highest performing rare-earth-free magnetostrictive materials; however, magnetostriction becomes sharply suppressed beyond x = 19% due to the formation of a parasitic ordered intermetallic phase. Here, we harness epitaxy to extend the stability of the BCC Fe1−xGax alloy to gallium compositions as high as x = 30% and in so doing dramatically boost the magnetostriction by as much as 10x relative to the bulk and 2x larger than canonical rare-earth based magnetostrictors. A Fe1−xGax − [Pb (Mg1/3Nb2/3)O3]0.7−[PbTiO3]0.3 (PMN-PT) composite magnetoelectric shows robust 90° electrical switching of magnetic anisotropy and a converse magnetoelectric coefficient of 2.0 × 10−5 s m−1. When optimally scaled, this high coefficient implies stable switching at ~80 aJ per bit.

Full text available from Nat Commun

Additionally see the report from The Michigan Engineering News Center ‘Harnessing the hum‘ and the report in Popular Science ‘How shape-shifting magnets could help build a lower-emission computer‘

Filed Under: Publications

Peter defends his PhD dissertation! Congratulations Peter!

March 24, 2021 By Matt Webb

Today, Peter gave a great defense of his PhD dissertation, titled “Disorder-Engineering of Ferroic Properties“. Congratulations Peter! The Ferroelectronics Lab wishes you the very best luck in your future work!

Filed Under: Graduate Student Progress

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News

  • Sieun defends her PhD dissertation! Congratulations Sieun! May 10, 2022
  • New Publication! “Effects of local compositional and structural disorder on vacancy formation in entropy-stabilized oxides from first-principles” April 29, 2022
  • New Publication! “Scalable Synthesis of Monolayer Hexagonal Boron Nitride on Graphene with Giant Bandgap Renormalization” April 18, 2022

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About

Our work is multidisciplinary. We employ concepts and tools from the fields of materials science, chemistry, physics and electrical engineering to develop new methods to investigate and engineer … Read More

News

Sieun defends her PhD dissertation! Congratulations Sieun!

May 10, 2022 By Matt Webb

New Publication! “Effects of local compositional and structural disorder on vacancy formation in entropy-stabilized oxides from first-principles”

April 29, 2022 By Matt Webb

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Ferroelectronics Lab
Address: 2030 H.H. Dow

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