Iron-based n-type electron-induced ferromagnetic semiconductor
Iron-based n-type electron-induced ferromagnetic semiconductor
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发表时间：
2011-06
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通讯作者：
P. Hai;L. D. Anh;Masaaki Tanaka
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作者：
P. Hai;L. D. Anh;Masaaki Tanaka
载流子诱导铁磁半导体（FMS）已经被深入研究了几十年，因为它们具有传统金属材料无法实现的新功能。其中包括通过电选通或光照射控制磁性的能力，同时充分继承了半导体材料的优势，如能带工程。然而，原型FMS（例如（In，Mn）As或（Ga，Mn）As）总是p型的，使得难以用于真实的自旋器件。这是因为这些材料中的锰（Mn）原子作为局部磁矩和受体工作，为载流子介导的铁磁性提供空穴。在这里，我们表明，通过引入铁（Fe）到InAs中，它是可能的制造一个新的FMS的能力，控制铁磁性的Fe和独立的载流子掺杂。尽管人们普遍认为四面体Fe-As键是反铁磁的，但我们证明了掺杂电子的（In，Fe）As表现为n型电子诱导的FMS，这是几十年来半导体自旋电子学中缺失的一部分。这一成就为实现新型自旋器件（如自旋发光二极管或自旋场效应晶体管）开辟了道路，并有助于理解FMS中载流子介导的铁磁性机制。
Carrier-induced ferromagnetic semiconductors (FMSs) have been intensively studied for decades as they have novel functionalities that cannot be achieved with conventional metallic materials. These include the ability to control magnetism by electrical gating or light irradiation, while fully inheriting the advantages of semiconductor materials such as band engineering. Prototype FMSs such as (In,Mn)As or (Ga,Mn)As, however, are always p-type, making it difficult to be used in real spin devices. This is because manganese (Mn) atoms in those materials work as local magnetic moments and acceptors that provide holes for carrier-mediated ferromagnetism. Here we show that by introducing iron (Fe) into InAs, it is possible to fabricate a new FMS with the ability to control ferromagnetism by both Fe and independent carrier doping. Despite the general belief that the tetrahedral Fe-As bonding is antiferromagnetic, we demonstrate that (In,Fe)As doped with electrons behaves as an n-type electron-induced FMS, a missing piece of semiconductor spintronics for decades. This achievement opens the way to realise novel spin-devices such as spin light-emitting diodes or spin field-effect transistors, as well as helps understand the mechanism of carrier-mediated ferromagnetism in FMSs.