Metal insulator transitions in perovskite SrIrO3 thin films
Metal insulator transitions in perovskite SrIrO3 thin films
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DOI：
10.1063/1.4903314
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发表时间：
2014-12-07
影响因子：
3.2
通讯作者：
Jeong, Yoon Hee
中科院分区：
文献类型：
--
作者：
Biswas, Abhijit;Kim, Ki-Seok;Jeong, Yoon Hee
由Anderson定域化(无序)和/或Mott定域化(关联)驱动的强关联系统中金属绝缘体相变的理解是凝聚态物理学中的一个长期问题。主要的基本问题是，这两种机制是如何实现突发异常行为的。在这里，我们在GdScO_3(110)、DyScO_3(110)、SrTiO_3(001)和NdGaO_3(110)等不同晶格失配的衬底上生长了高质量的钙钛矿型SrIrO_3薄膜，包括强自旋轨道耦合的5d元素Ir，以便对其输运性质进行系统的研究。我们发现，通过减小薄膜厚度(在最佳晶格匹配的衬底上)或改变晶格应变的程度(通过薄膜与衬底之间的晶格失配)，可以在该系统中诱导金属绝缘体相变。令人惊讶的是，这两条路径寻找了两种不同类型的金属绝缘体相变：前者属于无序驱动的Anderson类型，而后者则是无序和关联相互作用的非传统Mott-Anderson类型。更有趣的是，在SrIrO_3的金属相中，随着晶格应变的增加，电阻率呈现出不寻常的非费米液体特征，表现为与T-e成正比，e从4/5演化到1到3/2。我们讨论了这些现象的理论含义，以阐明金属绝缘体的相变。(C)2014 AIP出版有限责任公司。
Understanding of metal insulator transitions in a strongly correlated system, driven by Anderson localization (disorder) and/or Mott localization (correlation), is a long standing problem in condensed matter physics. The prevailing fundamental question would be how these two mechanisms contrive to accomplish emergent anomalous behaviors. Here, we have grown high quality perovskite SrIrO3 thin films, containing a strong spin orbit coupled 5d element Ir, on various substrates such as GdScO3 (110), DyScO3 (110), SrTiO3 (001), and NdGaO3 (110) with increasing lattice mismatch, in order to carry out a systematic study on the transport properties. We found that metal insulator transitions can be induced in this system; by either reducing thickness (on best lattice matched substrate) or changing degree of lattice strain (by lattice mismatch between film and substrates) of films. Surprisingly these two pathways seek two distinct types of metal insulator transitions; the former falls into disorder driven Anderson type whereas the latter turns out to be of unconventional Mott-Anderson type with the interplay of disorder and correlation. More interestingly, in the metallic phases of SrIrO3, unusual non-Fermi liquid characteristics emerge in resistivity as Delta rho proportional to T-e with e evolving from 4/5 to 1 to 3/2 with increasing lattice strain. We discuss theoretical implications of these phenomena to shed light on the metal insulator transitions. (C) 2014 AIP Publishing LLC.