Conducting Domain Walls in Lithium Niobate Single Crystals

Abstract

Ferroic materials play an increasingly important role in novel (nano)electronic devices. Recently, research on domain walls (DWs) receives a big boost by the discovery of DW conductivity (DWC) in BiFeO3 and Pb(ZrxTi1‐x)O3 ferroic thin films. Here, it is demonstrated that DWC is not restricted to thin films, but equally applies to millimeter‐thick wide‐bandgap, ferroic single crystals, such as LiNbO3. In this material transport along DWs can be switched by super‐bandgap illumination and tuned by engineering the tilting angle of DWs with respect to the polar axis. The results are consistently obtained using conductive atomic force microscopy to locally map the DWC and macroscopic contacts, thereby in addition investigating the temperature dependence, DW transport activation energies, and relaxation behavior.

Towards reversible control of domain wall conduction in Pb(Zr0.2Ti0.8)O3 thin films

“…12,13 The defect states can also be photo-activated, temporarily inducing, or enhancing domain wall currents by supra-bandgap illumination. 14,15 Here, we show that by using a moderate temperature, ultrahigh vacuum (UHV) annealing and ambient exposure, domain wall currents in PZT thin films can be reversibly controlled, allowing either conductive or insulating behavior, stable over the multi-week period of measurement. We propose a qualitative mechanism based on changes induced in surface adsorbates and oxygen vacancy distribution.…”

Polarization control at spin-driven ferroelectric domain walls

“…Exotic domain-wall phenomena are observed in archetypal ferroelectrics, such as BaTiO 3 (refs 12,13), PbZr 0.2 Ti 0.8 O 3 (refs 7,14,15) and LiNbO 3 (ref. 16), where metastable charged domain walls can be induced by, for example, electric fields 17 . Additional degrees of freedom arise in so-called improper ferroelectrics, where the polarization emerges due to the coupling to a primary structural or magnetic order parameter.…”

Эволюция Доменной Структуры И Формирование Заряженных Доменных Стенок При Переключении Поляризации В Монокристаллах Ниобата Лития, Модифицированных Отжигом В Вакууме

“…Одним из самых распространенных способов создания регулярной доменной структуры является переключение поляризации приложением пространственно неоднород-ного электрического поля с помощью системы полосо-вых электродов [6]. Создание нанодоменных структур с высокой концентрацией нейтральных и заряженных доменных стенок (ЗДС), так называемая инженерия доменных стенок (engineering of domain boundaries), позволяет существенно улучшать пьезоэлектрические свойства кристаллов [8][9][10]. Следует отметить, что в LN разработаны методики формирования квазирегулярных нанодоменных структур в сильно неравновесных услови-ях переключения [4][5][6].…”