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陆旭兵小组关于BaTiO3输运的工作AEM在线发表

2015/4/27 13:52:07      点击:      发布:管理员
M. Li, J. Zhou, X. S. Jing, M. Zeng, S. J. Wu, J. W. Gao, Z. Zhang, X. S. Gao, X. B. Lu(陆旭兵), J.-M. Liu, and M. Alexe


Controlling Resistance Switching Polarities of Epitaxial BaTiO3 Films by Mediation of Ferroelectricity and Oxygen Vacancies


Advanced Electronic Materials 1, 1500069 (2015)


材料科学基础告诉我们材料根据其输运行为大概可以被分为几类。这些类别注定了对应的材料各自为用、井水河水相邻而居。这是我们对材料分类范式的理解。

不过,现在凝聚态物理和材料科学经常打擦边球,叫嚣一些新的观点:即材料可以属于这一类,也可以属于那一类,就看是什么人去把玩这些材料了。其中一种把玩方式就是将绝缘体说成是金属,如SrTiO3/LaAlO3界面的二维电子气。

其实,有一些传统绝缘体材料也可以被玩成金属。陆旭兵博士在这里就是通过高真空下制备铁电BaTiO3薄膜,使得其可以展示很好的导电性、甚至是金属性。本工作报道BaTiO3-δ 薄膜的高导电阻变行为,这种行为还可以通过铁电极化和氧空位来调控这种阻变行为,令人印象深刻。

类似绝缘体功能材料付诸阻变应用的工作最近几年很多,各种花样也层出不穷。这里不再过多啰嗦。

这里需要提一点的是,Advanced Materials受Nature的诱惑,这几年也推出了基于专门化功能的以Advanced开头、以Materials结尾的新刊物。本工作发表于刚刚创刊不久的Advanced Electronic Materials,以与其兄长期刊Advanced Functional Materials和Advanced Energy Materials对应。事实上,Nature违规超生了很多子刊之后,其所在出版社竟然还收购了Advanced Materials一族所在的出版社,使得Advanced Materials超生很多子刊变得合规和合理,与当下中国计划生育形态的演变惺惺相惜。陆旭兵博士对此应该体会深刻。:)

In this work, the observations of different resistive switching polarities of epitaxial BaTiO3 (BTO) thin films fabricated by pulsed laser deposition are reported. The BTO films with various ferroelectric states and oxygen vacancy (VO) concentrations are achieved by carefully controlling the oxygen pressure during the depositions. For films with no ferroelectricity and high VO concentrations, the resistance will change from a low resistance state (LRS) to a high resistance state (HRS) during a positive voltage cycle (0 → 3 → 0 V), and from a HRS to a LRS during a negative voltage cycle (0 → −3 → 0 V). However, completely opposite RS polarity is observed for the films with weak ferroelectricity and intermediate VO concentrations. Such RS behaviors and polarity can be hardly observed or negligible for the films with good ferroelectricity and nearly free of VO. It is proposed that the unique resistance switching polarities of BTO films are attributed to the competition between the ferroelectricity and oxygen vacancy migration dynamics. Results clarify the complex RS mechanisms in the BTO films, and address the competing ferroelectricity and VO migration in modulating the RS behaviors of ferroelectric oxide-based resistive memory devices.

URL:

http://dx.doi.org/10.1002/aelm.201500069