該研究提出了一種新的電子工程材料的設計概念，為單相材料中鐵電、磁性和導電性的異常共存提供了可能。來自上海材料基因組研究所的徐濤博士和日本京都大學的Takahiro Shimada博士共同領導的團隊，使用第一原理計算證明了適當的機械應變可以通過調節電子-聲子耦合，將摻雜BaTiO3中過量電子從自由載流子構型轉變為局域極化態。機械應變為通過電子-聲子耦合來調節電子的形狀和構型提供了一種可行的手段，並導致電子摻雜的BaTiO3中存在多鐵極化子。這些多鐵性質進一步與電子導電性共存，該現象源於電子極化子的強遷移率。因此，通過機械調控有意地對改變電子結構，可能成為一種有希望實現不尋常的共存特性和新技術突破的範例。該文近期發表於npj Computational Materials 5:23(2019)。
Summary
Epitaxial BaTiO3: A new electron engineering materials
A new material design concept for electron engineering is proposed, which provides a possibility for the unusual coexistence of the ferroelectricity, magnetism, and conductivity in a single-phase material. A team co-led by Tao Xu and Takahiro Shimada from the Shanghai Materials Genome Institute, China, and Kyoto University, Japan, respectively, used first principles calculations to demonstrate that appropriate mechanical strain can turn the excess electrons in doped BaTiO3 from a free-carrier configuration to a localized polaronic state by modulating the electron–phonon coupling. The mechanical strain provides a viable means to modulate the shape and configuration of electrons through the modulation of electron–phonon coupling and results in the multiferroic polaron in electron-doped BaTiO3. These multiferroic properties further coexist with the electronic conductivity, which originates from the intense mobility of electron polarons. Therefore, the deliberate mechanical control over the electron configuration may become a promising paradigm for unusual coexisting properties and new technology breakthroughs. This article was recently published in npj Computational Materials 5:23(2019) .
原文Abstract及其翻譯
Electron engineering of metallic multiferroic polarons in epitaxial BaTiO3 (外延BaTiO3中金屬多鐵性極化子的電子工程)
Tao Xu, Takahiro Shimada, Yasumitsu Araki, Masataka Mori, Gen Fujimoto, Jie Wang, Tong-Yi Zhang & Takayuki Kitamura
Abstract The coexistence of ferroelectricity, conductivity, and magnetism in a single-phase material has attracted considerable attention due to fundamental interest and tremendous technological potential. However, their mutually exclusive mechanisms hinder the discovery of multifunctional conducting multiferroics. Here, we propose a new material design approach for electron engineering to enable these conflicting properties to coexist. We use first principles calculations to demonstrate that appropriate mechanical strain can turn the excess electrons in doped BaTiO3 from a free-carrier configuration to a localized polaronic state by modulating the electron–phonon coupling. The resulting localized spin-polarized electron survives the host ferroelectricity and consequently manifests as a multiferroic polaron. The multiferroic properties coexist with the electronic conductivity arising from the high-hopping mobility of the polaron, which enables the doped epitaxial BaTiO3 to act as a multiferroic conducting material. This mechanical control over the electron configuration is a potential path toward unusual coexisting properties.
摘要單相材料中鐵電性、導電性和磁性的共存具有巨大的技術和應用潛力，引起了人們的廣泛關注。然而，它們相互排斥的機制妨礙了多功能導電多鐵材料的發現。本研究提出了一種新的材料設計方法，以通過電子能帶工程使這些相互矛盾的材料性質可以共存。我們使用第一原理計算證明，適當的機械應變可以通過調節電子-聲子耦合，將摻雜BaTiO3中過量電子從自由載流子構型轉變為局域極化態。所得到的局域自旋極化電子在主鐵電性作用下仍然存在，因而表現為多鐵極化子。多鐵性與極化子的高躍遷遷移率引起的電子導電性共存，使摻雜外延BaTiO3能夠成為一種多鐵性導電材料。這種對電子構型的機械控制是一種潛在的途徑，可以使材料獲得不同尋常的共存特性。
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