磁性材料，特別是鐵磁半導(dǎo)體，可以與現(xiàn)代半導(dǎo)體工藝進(jìn)行集成，因此往往被認(rèn)為是自旋電子學(xué)領(lǐng)域中的理想材料。除了本征磁性半導(dǎo)體外，過渡金屬摻雜的稀磁半導(dǎo)體也得到廣泛研究。另外，不含d/f電子的室溫d⁰鐵磁半導(dǎo)體也是磁性材料研究的一個(gè)重要分支。由于空穴媒介作用被認(rèn)為是“d⁰鐵磁性”的起源，且可以通過摻雜甚至缺陷來實(shí)現(xiàn)，這種“d⁰鐵磁性”為尋找高溫自旋電子材料提供了不同的方案與可能性。與此同時(shí)，在過去十年里，二維本征鐵磁材料也快速發(fā)展，甚至已有一些自旋隧道結(jié)的測量研究。

然而，二維本征鐵磁材料十分缺乏，且它們普遍擁有較低的居里溫度，不利于低維自旋電子學(xué)器件的發(fā)展與應(yīng)用。近年來研究者逐漸將目光移至摻雜誘導(dǎo)的二維d⁰鐵磁半導(dǎo)體，但是系統(tǒng)的研究依舊缺乏，且自旋極化空穴的交換耦合與非局域化機(jī)制尚不清晰。

來自荷語魯汶大學(xué)物理天文學(xué)院的Ruishen Meng教授與Michel Houssa教授合作，從三個(gè)主流數(shù)據(jù)庫中篩選了數(shù)千個(gè)二維非磁半導(dǎo)體，并借助高通量密度泛函理論計(jì)算，確定出了空穴摻雜引起磁性的潛在候選材料。

他們對(duì)材料進(jìn)行了穩(wěn)定性計(jì)算，最終確定出122種穩(wěn)定的二維材料。這些材料均可以由空穴摻雜實(shí)現(xiàn)穩(wěn)定的磁有序，并且部分體系的居里溫度達(dá)到了室溫。最后，他們還討論了鐵磁有序的交換相互作用。

該工作大大豐富了二維磁性材料庫，同時(shí)對(duì)空穴摻雜誘導(dǎo)鐵磁材料提供了一定的理論見解，為將來實(shí)現(xiàn)二維自旋電子器件打下了一定基礎(chǔ)。相關(guān)論文近期發(fā)布于npj Computational Materials 8: 230 (2022)。

Editorial Summary

Magnetic materials, especially ferromagnetic semiconductors, are considered advantageous in the field of spintronics because of their easy integration into semiconductor devices. Apart from the intrinsic magnetic materials, research attention has also been focusing on dilute magnetic semiconductors (DMSs). Besides, room temperature d⁰FM semiconductor without d/f electrons is also an important branch of magnetic materials. As hole mediation is considered to be the origin of the ‘d⁰ferromagnetism’, which can be realized by acceptor doping or even by intrinsic defects, the ‘d⁰ ferromagnetism’ offers a different way and possibility to hunt for high-temperature spintronic materials. Meanwhile, the past decade has witnessed the rapid development of 2D magnetic materials and even 2D tunneling junctions. However, the scarcity of 2D FM semiconductors and their rather low Curie temperature (Tc) hamper practical applications as well as the further investigation of 2D magnetism. In the recent years, studies have predicted several (hole-)doping induced 2D d⁰ FM semiconductors. However, a systematic investigation of the magnetic properties of these 2D materials is still lacking. The mechanism responsible for the exchange coupling and delocalization of the spin-polarized holes has not been discussed yet.?

A team led by Prof. Ruishen Meng and Prof. Michel Houssa from the Department of Physics and Astronomy in KU Leuven Celestijnenlaan 200D, screened thousands of 2D non-magnetic semiconductors/insulators from three databases, and performed a high-throughput density functional theory calculation to identify potential 2D FM materials induced by hole doping. They then verified the stability of the potential candidates, for which 122 materials were recognized as stable 2D FM materials upon hole doping. The computed Curie temperatures of some systems were close to or above room temperature. At last, the exchange interaction mechanisms responsible for the FM coupling in these 2D materials were also discussed. This work not only provides theoretical insights into hole-doped 2D FM materials, but also enriches the family of 2D magnetic materials for possible spintronic applications, laying a certain foundation for the realization of two-dimensional spintronic devices in the future. This article was recently published in npj Computational Materials 8: 230 (2022).

原文Abstract機(jī)器翻譯

Abstract?Two-dimensional (2D) ferromagnetic materials are considered as promising candidates for the future generations of spintronic devices. Yet, 2D materials with intrinsic ferromagnetism are scarce. Hereby, high-throughput first-principles simulations are performed to screen 2D materials that present a non-magnetic to a ferromagnetic transition upon hole doping. A global evolutionary search is subsequently performed to identify alternative possible atomic structures of the eligible candidates, and 122 materials exhibiting a hole-doping induced ferromagnetism are identified. Their energetic and dynamic stability, as well as magnetic properties under hole doping are investigated systematically. Half of these 2D materials are metal halides, followed by chalcogenides, oxides, and nitrides, some of them having predicted Curie temperatures above 300?K. The exchange interactions responsible for the ferromagnetic order are also discussed. This work not only provides theoretical insights into hole-doped 2D ferromagnetic materials, but also enriches the family of 2D magnetic materials for possible spintronic applications.

摘要二維（2D）鐵磁材料是未來建構(gòu)自旋電子器件有前途的候選材料。然而，具有本征鐵磁性的二維材料相當(dāng)稀缺。在此，通過高通量第一性原理模擬，我們篩選出了一系列二維材料，它們會(huì)在空穴摻雜條件下呈現(xiàn)出非磁性到鐵磁序的轉(zhuǎn)變。隨后，我們進(jìn)行了全局演化搜索其他可能的結(jié)構(gòu)，最終確定了122種表現(xiàn)出空穴摻雜誘導(dǎo)鐵磁性的二維材料。我們系統(tǒng)地研究了它們在摻雜時(shí)的能量和動(dòng)力學(xué)穩(wěn)定性以及磁學(xué)性質(zhì)。這些二維材料有一半是金屬鹵化物，其次是硫族化合物、氧化物和氮化物，其中一些材料的居里溫度可以超過300 K。我們還討論了鐵磁序相關(guān)的交換相互作用。這項(xiàng)工作不僅為空穴摻雜的二維鐵磁材料提供了理論見解，而且大大豐富了二維磁性材料家族，有望實(shí)現(xiàn)自旋電子器件應(yīng)用。