The IRG is aimed at exploring and exploiting ferroelectric (FE) polarization as a state variable that allows realization of polarization-controlled electronic, transport, and other functional properties of oxide, organic, and hybrid FE-based structures. This involves ferroelectrically induced resistive switching phenomena and the associated memristive behavior, FE modulation of electronic confinement at the hybrid FE/semiconductor and organic interfaces, as well as development of novel functional systems based on newly synthesized organic ferroelectrics where molecular interactions are responsible for macroscopic dipole ordering. These scientifically rich problems comprise the involvement of multiple degrees of freedom, the critical role of interfaces, and the interplay between physical and chemical properties at the nanoscale. They require comprehensive fundamental understanding and hold a lot of promise for technological innovations, including new paradigms for data storage and conceptually novel photovoltaic applications.
IRG 2 Researchers
Alexei Gruverman (coordinator) - PFM, CAFM
Stephen Ducharme - Langmuir-Blodgett, dielectric testing
Chang-Beom Eom - PLD
Xia Hong - Oxide sputtering, nanofab
Jinsong Huang - Hybrid structures
Alexander Sinitskii - Chem. synthesis, devices
Evgeny Tsymbal - Theory spin transport and oxide FE
Xiao Cheng Zeng - Theory organic FE
Research Thrust 1:
Polarization-controlled Electronic Transport
Thrust 1 is focused on the electrically controlled transport properties in tunneling systems where FE polarization drives giant resistive switching effects through the modulation of the tunneling barrier and induced metalinsulator transitions at the interface.
- Switchable interface resistance
- TER driven by interfacial phase transitions
- Interface chemistry effect on TER
- Voltage-free control of TER
Research Thrust 2:
Polarization-enabled Functional Hybrid Structures
Thrust 2 is centered on polarization-enabled electronic properties of hybrid FE interfaces where electronic confinement gives rise to novel phenomena, which are promising for unconventional electronic devices with new functionalities.
- Polarization-mediated modulation of graphene electronic properties
- Polarization-induced phase transitions in shape-memory alloys
- Polarization-enhanced photovoltaic effects
Research Thrust 3:
Polarization States in Low-dimension Molecular Ferroelectrics
Thrust 3 is focused on polarization states in novel low-dimensional molecular ferroelectrics where macroscopic ordering is controlled at the molecular level providing new approaches towards polarization-functionalized heterostructures.
- Charge transfer complexes
- Planar proton-transfer systems
- Molecular toggling systems
IRG 2 Highlights:
» Nano Letters 2017
Tao Li (U Nebraska/Lincoln), Pankaj K. Sharma (U Nebraska/Lincoln), Alexey Lipatov (U Nebraska/Lincoln), Hyungwoo Lee (U of Wisconsin/Madison), Jung-Woo Lee (U of Wisconsin/Madison), Mikhail Y. Zhuravlev (Kurnakov Institute, Moscow, Russia), Tula R. Paudel (U Nebraska/Lincoln), Yuri A. Genenko (TU Darmstadt), Chang-Beom Eom (U of Wisconsin/Madison), Evgeny Tsymbal (U Nebraska/Lincoln), Alexander Sinitskii (U Nebraska/Lincoln), Alexei Gruverman (U Nebraska/Lincoln), "Polarization-Mediated Modulation of Electronic and Transport Properties of Hybrid MoS2−BaTiO3−SrRuO3 Tunnel Junctions," Nano Letters DOI: 10.1021/acs.nanolett.6b04247 (2017).
» Advanced Materials 2016
Q. Dong, J. Song, Y. Fang, Y. Shao, S. Ducharme, and J. Huang, “Lateral-Structure Single-Crystal Hybrid Perovskite Solar Cells via Piezoelectric Poling,” Adv. Mater. 28, 2816-2821 (2016).
» Science 2015
D. Lee, H. Lu, Y. Gu, S.-Y. Choi, S.-D. Li, S. Ryu, T. R. Paudel, K. Song, E. Mikheev, S. Lee, S. Stemmer, D. A. Tenne, S. H. Oh, E. Y. Tsymbal, X. Wu, L.-Q. Chen, A. Gruverman, and C. B. Eom, "Emergence of Room-temperature Ferroelectricity at Reduced Dimensions," Science 349, Issue 6254, 1314-1317 (2015).
» Advanced Materials 2015
H. Lu, T. Li, S. Poddar, O. Goit, A. Lipatov, A. Sinitskii, S. Ducharme, and A. Gruverman, "Statics and Dynamics of Ferroelectric Domains in Diisopropylammonium Bromide," Adv. Mater. 27, 7832–7838 (2015).
» ACS Nano 2015
A. Lipatov, P. Sharma, A. Gruverman, and A. Sinitskii, "Optoelectrical Molybdenum Disulfide (MoS2)--Ferroelectric Memories," ACS Nano 9 (8), 8089–8098 (2015).
» Nature Communications 2014
H. Lu, A. Lipatov, S. Ryu, D. J. Kim, M. Y . Zhuravlev, C. B. Eom, E. Y. Tsymbal, A. Sinitskii, and A. Gruverman, “Ferroelectric tunnel junctions with graphene electrodes,” Nature Comm. 5, 5518 (2014).
» Nano Letters 2014
R. G. P. McQuaid, A. Gruverman, J. F. Scott, and J. M. Gregg, “Exploring vertex interactions in ferroelectric flux-closure domains,” Nano Lett. 14, 4230-4237 (2014).