Abstract
Ferroelectric domain walls have continued to attract widespread attention due to both the novelty of the phenomena observed and the ability to reliably pattern them in nanoscale dimensions. However, the conductivity mechanisms remain in debate, particularly around nominally uncharged walls. Here, we posit a conduction mechanism relying on field-modification effect from polarization re-orientation and the structure of the reverse-domain nucleus. Through conductive atomic force microscopy measurements on an ultra-thin (001) BiFeO3 thin film, in combination with phase-field simulations, we show that the field-induced twisted domain nucleus formed at domain walls results in local-field enhancement around the region of the atomic force microscope tip. In conjunction with slight barrier lowering, these two effects are sufficient to explain the observed emission current distribution. These results suggest that different electronic properties at domain walls are not necessary to observe localized enhancement in domain wall currents.
| Original language | English |
|---|---|
| Article number | 1318 |
| Journal | Nature Communications |
| Volume | 8 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2017 |
Funding
This research was sponsored by the Division of Materials Sciences and Engineering, BES, US DOE (R.K.V., S.V.K., P.M., Y.C.). Research was conducted at the Center for Nano-phase Materials Sciences, which also provided support (A.I.) and which is a US DOE Office of Science User Facility. N.L. acknowledges support from the Eugene P. Wigner Fellowship program at Oak Ridge National Lab. X-ray data was collected at the Advanced Photon Source which is a DOE Office of Science User Facility. The work in National Chiao Tung university is supported by the Ministry of Science and Technology (MOST 103-2119-M-009-003-MY3 and MOST 104-2628-E-009-005-MY2), Taiwan and Academia Sinica Research Program on Nanoscience and Nanotechnology of Taiwan. The effort at Penn State is supported by the U.S. DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02-07ER46417 (LQC).