Orbital, spin and charge fluctuations in layered oxide heterostructures

层状氧化物异质结构中的轨道、自旋和电荷波动

• 批准号: 229238168
• 负责人: Professor Dr. Giorgio Sangiovanni
• 金额: --
• 依托单位: Institut für Theoretische Physik und Astrophysik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/229238168?language=en
• 关键词: Orbital; spin; charge; fluctuations; layered

The goal of this project is to investigate layered heterostructures of transition-metal oxides by means of band-structure calculations as well as tailor-made implementations of Dynamical Mean Field Theory and its extensions. A theoretical understanding of these novel materials, which can nowadays be grown in a controlled way, is going to benefit not only basic research on electronic properties at interfaces but also technological development and device fabrication. In particular, an ab-initio study is particularly timely, as the stunning discovery by A. Ohtomo and H. Hwang [Nature 419, 378 (2002)] that the interface between a band- (i.e., standard) insulator like SrTiO3 and a Mott- (i.e., strongly-correlated) insulator like LaTiO3 can be conducting has not yet been followed by a fully satisfactory theoretical explanation. In addition, new heterostructures containing other materials with partially filled d-shells are currently in the spotlight (e.g., LaVO3/SrTiO3). This increases the need of an understanding of electronic correlation effects in systems that are far from the conventional bulk limit. There are many questions that need to be answered, such as whether or not alternating positive LaO and negative TiO2 layers give rise to a nonzero potential gradient in the LaTiO3 part and also to what extent this is related to the existence of a critical LaTiO3 thickness above which the interface becomes metallic. Furthermore, it is very important to assess if one can describe within the same theoretical framework LaVO3/SrTiO3 and what the orbital character of the mobile carriers at the interface is. Density Functional Theory calculations and new implementations of Dynamical Mean Field Theory specifically designed to treat inequivalent layers can reliably take into account, on the one hand, the electronic structure and, on the other, the effects of strong electronic correlation. Our study can therefore clarify some of the open questions and stimulate the synthesis of new heterostructures with distinct functionalities.

本项目的目标是通过带结构计算以及动态平均场理论及其扩展的定制实现来研究过渡金属氧化物的层状异质结构。对这些新型材料的理论理解，现在可以以一种可控的方式生长，不仅有利于界面电子特性的基础研究，也有利于技术发展和器件制造。特别是，一项ab-initio研究尤其及时，因为a . Ohtomo和H. Hwang [Nature 419,378(2002)]惊人的发现，带状（即标准）绝缘体（如SrTiO3）和莫特-（即强相关）绝缘体（如LaTiO3）之间的界面可以导电，但尚未得到完全令人满意的理论解释。此外，含有其他部分填充d壳层材料的新型异质结构（如LaVO3/SrTiO3）目前也受到关注。这增加了对系统中电子相关效应的理解的需要，这些系统远离传统的体积限制。有许多问题需要回答，例如，交替的正LaO和负TiO2层是否会在LaTiO3部分产生非零电位梯度，以及这在多大程度上与临界LaTiO3厚度的存在有关，超过该厚度，界面就会变成金属。此外，评估是否可以在相同的理论框架内描述LaVO3/SrTiO3以及界面上移动载流子的轨道特征是非常重要的。密度泛函理论计算和专门设计用于处理不等价层的动态平均场理论的新实现，一方面可以可靠地考虑到电子结构，另一方面，强电子相关性的影响。因此，我们的研究可以澄清一些悬而未决的问题，并促进具有不同功能的新异质结构的合成。

项目成果

Quantized electronic fine structure with large anisotropy in ferromagnetic Fe films

铁磁Fe薄膜中具有大各向异性的量子化电子精细结构

• DOI: 10.1103/physrevb.90.035136
• 发表时间: 2014
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: C. Seibel;A. Nuber;H. Bentmann;M. Mulazzi;P. Blaha;G. Sangiovanni;F. Reinert
• 通讯作者: F. Reinert

Shifting the Voltage Drop in Electron Transport Through a Single Molecule.

• DOI: 10.1103/physrevlett.115.016802
• 发表时间: 2015-06
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: S. Karan;D. Jacob;M. Karolak;C. Hamann;Yongfeng Wang;A. Weismann;A. Lichtenstein;R. Berndt

Effective crystal field and Fermi surface topology: a comparison of d- and dp-orbital models

有效晶体场和费米表面拓扑：d 和 dp 轨道模型的比较

• DOI: 10.1103/physrevb.88.195116
• 发表时间: 2013
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: N. Parragh;G. Sangiovanni;P. Hansmann;S. Hummel;K. Held;A. Toschi
• 通讯作者: A. Toschi

Nickel-titanium double perovskite: A three-dimensional spin-1 Heisenberg antiferromagnet

• DOI: 10.1103/physrevb.91.075108
• 发表时间: 2014-07
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: M. Karolak;M. Edelmann;G. Sangiovanni

Many-body effects on Cr(001) surfaces: An LDA plus DMFT study

Cr(001) 表面的多体效应：LDA 加 DMFT 研究

• DOI: 10.1103/physrevb.93.195115
• 发表时间: 2016
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: M. Schüler;S. Barthel;M. Karolak;A. I. Poteryaev;A. I. Lichtenstein;M. I. Katsnelson;G. Sangiovanni;T. Wehling
• 通讯作者: T. Wehling