Bipolar Carrier (e⁻/h⁺) Layer on Clean Surface of Insulating BaTiO₃ Crystal Intrinsic to Ferroelectrics

Abstract

We report experimental observation of electron (e ⁻)/hole (h ⁺) layer on the clean surface of insulating pure BaTiO₃ single crystals in ultra high vacuum (UHV < 10⁻⁸ Pa). To our knowledge this is the first report of the bipolar surface carrier layer by the field effect on any oxide. The experiments here verify that both accumulation and inversion occur and the surface carrier layer is intrinsic, i.e., due to spontaneous polarization P _S not to impurities and defects.

Keywords:

• Surface
• nano
• depolarization
• field effect
• ferroelectric

Acknowledgments

This work is supported by Grants-in-aid for Scientific Research from JSPS No. 19340084.