Anisotropic polarization-induced conductance at a ferroelectric–insulator interface

Yi Zhang, Haidong Lu, Lin Xie, Xingxu Yan, Tula R. Paudel, Jeongwoo Kim, Xiaoxing Cheng, Hui Wang, Colin Heikes, Linze Li, Mingjie Xu, Darrell G. Schlom, Long-qing Chen, Ruqian Wu, Evgeny Y. Tsymbal, Alexei Gruverman, Xiaoqing Pan

Research output: Contribution to journalLetter

5 Citations (Scopus)

Abstract

Coupling between different degrees of freedom, that is, charge, spin, orbital and lattice, is responsible for emergent phenomena in complex oxide heterostrutures1,2. One example is the formation of a two-dimensional electron gas (2DEG) at the polar/non-polar LaAlO3/SrTiO3 (LAO/STO)3–7 interface. This is caused by the polar discontinuity and counteracts the electrostatic potential build-up across the LAO film3. The ferroelectric polarization at a ferroelectric/insulator interface can also give rise to a polar discontinuity8–10. Depending on the polarization orientation, either electrons or holes are transferred to the interface, to form either a 2DEG or two-dimensional hole gas (2DHG)11–13. While recent first-principles modelling predicts the formation of 2DEGs at the ferroelectric/insulator interfaces9,10,12–14, experimental evidence of a ferroelectrically induced interfacial 2DEG remains elusive. Here, we report the emergence of strongly anisotropic polarization-induced conductivity at a ferroelectric/insulator interface, which shows a strong dependence on the polarization orientation. By probing the local conductance and ferroelectric polarization over a cross-section of a BiFeO3–TbScO3 (BFO/TSO) (001) heterostructure, we demonstrate that this interface is conducting along the 109° domain stripes in BFO, whereas it is insulating in the direction perpendicular to these domain stripes. Electron energy-loss spectroscopy and theoretical modelling suggest that the anisotropy of the interfacial conduction is caused by an alternating polarization associated with the ferroelectric domains, producing either electron or hole doping of the BFO/TSO interface.

Original languageEnglish (US)
Pages (from-to)1132-1136
Number of pages5
JournalNature nanotechnology
Volume13
Issue number12
DOIs
StatePublished - Dec 1 2018

Fingerprint

Two dimensional electron gas
Ferroelectric materials
Polarization
polarization
insulators
conduction
Electrons
Electron energy loss spectroscopy
Oxides
electron gas
Heterojunctions
Electrostatics
discontinuity
Anisotropy
electrons
degrees of freedom
energy dissipation
Gases
Doping (additives)
electron energy

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Zhang, Y., Lu, H., Xie, L., Yan, X., Paudel, T. R., Kim, J., ... Pan, X. (2018). Anisotropic polarization-induced conductance at a ferroelectric–insulator interface. Nature nanotechnology, 13(12), 1132-1136. https://doi.org/10.1038/s41565-018-0259-z
Zhang, Yi ; Lu, Haidong ; Xie, Lin ; Yan, Xingxu ; Paudel, Tula R. ; Kim, Jeongwoo ; Cheng, Xiaoxing ; Wang, Hui ; Heikes, Colin ; Li, Linze ; Xu, Mingjie ; Schlom, Darrell G. ; Chen, Long-qing ; Wu, Ruqian ; Tsymbal, Evgeny Y. ; Gruverman, Alexei ; Pan, Xiaoqing. / Anisotropic polarization-induced conductance at a ferroelectric–insulator interface. In: Nature nanotechnology. 2018 ; Vol. 13, No. 12. pp. 1132-1136.
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abstract = "Coupling between different degrees of freedom, that is, charge, spin, orbital and lattice, is responsible for emergent phenomena in complex oxide heterostrutures1,2. One example is the formation of a two-dimensional electron gas (2DEG) at the polar/non-polar LaAlO3/SrTiO3 (LAO/STO)3–7 interface. This is caused by the polar discontinuity and counteracts the electrostatic potential build-up across the LAO film3. The ferroelectric polarization at a ferroelectric/insulator interface can also give rise to a polar discontinuity8–10. Depending on the polarization orientation, either electrons or holes are transferred to the interface, to form either a 2DEG or two-dimensional hole gas (2DHG)11–13. While recent first-principles modelling predicts the formation of 2DEGs at the ferroelectric/insulator interfaces9,10,12–14, experimental evidence of a ferroelectrically induced interfacial 2DEG remains elusive. Here, we report the emergence of strongly anisotropic polarization-induced conductivity at a ferroelectric/insulator interface, which shows a strong dependence on the polarization orientation. By probing the local conductance and ferroelectric polarization over a cross-section of a BiFeO3–TbScO3 (BFO/TSO) (001) heterostructure, we demonstrate that this interface is conducting along the 109° domain stripes in BFO, whereas it is insulating in the direction perpendicular to these domain stripes. Electron energy-loss spectroscopy and theoretical modelling suggest that the anisotropy of the interfacial conduction is caused by an alternating polarization associated with the ferroelectric domains, producing either electron or hole doping of the BFO/TSO interface.",
author = "Yi Zhang and Haidong Lu and Lin Xie and Xingxu Yan and Paudel, {Tula R.} and Jeongwoo Kim and Xiaoxing Cheng and Hui Wang and Colin Heikes and Linze Li and Mingjie Xu and Schlom, {Darrell G.} and Long-qing Chen and Ruqian Wu and Tsymbal, {Evgeny Y.} and Alexei Gruverman and Xiaoqing Pan",
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Zhang, Y, Lu, H, Xie, L, Yan, X, Paudel, TR, Kim, J, Cheng, X, Wang, H, Heikes, C, Li, L, Xu, M, Schlom, DG, Chen, L, Wu, R, Tsymbal, EY, Gruverman, A & Pan, X 2018, 'Anisotropic polarization-induced conductance at a ferroelectric–insulator interface', Nature nanotechnology, vol. 13, no. 12, pp. 1132-1136. https://doi.org/10.1038/s41565-018-0259-z

Anisotropic polarization-induced conductance at a ferroelectric–insulator interface. / Zhang, Yi; Lu, Haidong; Xie, Lin; Yan, Xingxu; Paudel, Tula R.; Kim, Jeongwoo; Cheng, Xiaoxing; Wang, Hui; Heikes, Colin; Li, Linze; Xu, Mingjie; Schlom, Darrell G.; Chen, Long-qing; Wu, Ruqian; Tsymbal, Evgeny Y.; Gruverman, Alexei; Pan, Xiaoqing.

In: Nature nanotechnology, Vol. 13, No. 12, 01.12.2018, p. 1132-1136.

Research output: Contribution to journalLetter

TY - JOUR

T1 - Anisotropic polarization-induced conductance at a ferroelectric–insulator interface

AU - Zhang, Yi

AU - Lu, Haidong

AU - Xie, Lin

AU - Yan, Xingxu

AU - Paudel, Tula R.

AU - Kim, Jeongwoo

AU - Cheng, Xiaoxing

AU - Wang, Hui

AU - Heikes, Colin

AU - Li, Linze

AU - Xu, Mingjie

AU - Schlom, Darrell G.

AU - Chen, Long-qing

AU - Wu, Ruqian

AU - Tsymbal, Evgeny Y.

AU - Gruverman, Alexei

AU - Pan, Xiaoqing

PY - 2018/12/1

Y1 - 2018/12/1

N2 - Coupling between different degrees of freedom, that is, charge, spin, orbital and lattice, is responsible for emergent phenomena in complex oxide heterostrutures1,2. One example is the formation of a two-dimensional electron gas (2DEG) at the polar/non-polar LaAlO3/SrTiO3 (LAO/STO)3–7 interface. This is caused by the polar discontinuity and counteracts the electrostatic potential build-up across the LAO film3. The ferroelectric polarization at a ferroelectric/insulator interface can also give rise to a polar discontinuity8–10. Depending on the polarization orientation, either electrons or holes are transferred to the interface, to form either a 2DEG or two-dimensional hole gas (2DHG)11–13. While recent first-principles modelling predicts the formation of 2DEGs at the ferroelectric/insulator interfaces9,10,12–14, experimental evidence of a ferroelectrically induced interfacial 2DEG remains elusive. Here, we report the emergence of strongly anisotropic polarization-induced conductivity at a ferroelectric/insulator interface, which shows a strong dependence on the polarization orientation. By probing the local conductance and ferroelectric polarization over a cross-section of a BiFeO3–TbScO3 (BFO/TSO) (001) heterostructure, we demonstrate that this interface is conducting along the 109° domain stripes in BFO, whereas it is insulating in the direction perpendicular to these domain stripes. Electron energy-loss spectroscopy and theoretical modelling suggest that the anisotropy of the interfacial conduction is caused by an alternating polarization associated with the ferroelectric domains, producing either electron or hole doping of the BFO/TSO interface.

AB - Coupling between different degrees of freedom, that is, charge, spin, orbital and lattice, is responsible for emergent phenomena in complex oxide heterostrutures1,2. One example is the formation of a two-dimensional electron gas (2DEG) at the polar/non-polar LaAlO3/SrTiO3 (LAO/STO)3–7 interface. This is caused by the polar discontinuity and counteracts the electrostatic potential build-up across the LAO film3. The ferroelectric polarization at a ferroelectric/insulator interface can also give rise to a polar discontinuity8–10. Depending on the polarization orientation, either electrons or holes are transferred to the interface, to form either a 2DEG or two-dimensional hole gas (2DHG)11–13. While recent first-principles modelling predicts the formation of 2DEGs at the ferroelectric/insulator interfaces9,10,12–14, experimental evidence of a ferroelectrically induced interfacial 2DEG remains elusive. Here, we report the emergence of strongly anisotropic polarization-induced conductivity at a ferroelectric/insulator interface, which shows a strong dependence on the polarization orientation. By probing the local conductance and ferroelectric polarization over a cross-section of a BiFeO3–TbScO3 (BFO/TSO) (001) heterostructure, we demonstrate that this interface is conducting along the 109° domain stripes in BFO, whereas it is insulating in the direction perpendicular to these domain stripes. Electron energy-loss spectroscopy and theoretical modelling suggest that the anisotropy of the interfacial conduction is caused by an alternating polarization associated with the ferroelectric domains, producing either electron or hole doping of the BFO/TSO interface.

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U2 - 10.1038/s41565-018-0259-z

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JO - Nature Nanotechnology

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