Device Research Laboratory, Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA.
Nat Mater. 2010 Apr;9(4):337-44. doi: 10.1038/nmat2716. Epub 2010 Mar 7.
Electric-field manipulation of ferromagnetism has the potential for developing a new generation of electric devices to resolve the power consumption and variability issues in today's microelectronics industry. Among various dilute magnetic semiconductors (DMSs), group IV elements such as Si and Ge are the ideal material candidates because of their excellent compatibility with the conventional complementary metal-oxide-semiconductor (MOS) technology. Here we report, for the first time, the successful synthesis of self-assembled dilute magnetic Mn(0.05)Ge(0.95) quantum dots with ferromagnetic order above room temperature, and the demonstration of electric-field control of ferromagnetism in MOS ferromagnetic capacitors up to 100 K. We found that by applying electric fields to a MOS gate structure, the ferromagnetism of the channel layer can be effectively modulated through the change of hole concentration inside the quantum dots. Our results are fundamentally important in the understanding and to the realization of high-efficiency Ge-based spin field-effect transistors.
电场对铁磁性的操控有望开发新一代的电子器件，以解决当前微电子产业中的功耗和可变性问题。在各种稀磁半导体（DMS）中，硅（Si）和锗（Ge）等 IV 族元素是理想的候选材料，因为它们与传统的互补金属氧化物半导体（CMOS）技术具有极好的兼容性。在这里，我们首次成功合成了具有室温以上铁磁有序的自组装稀磁 Mn(0.05)Ge(0.95)量子点，并展示了在 100 K 下通过 MOS 铁磁电容器实现铁磁性的电场控制。我们发现，通过对 MOS 栅极结构施加电场，可以通过改变量子点内的空穴浓度来有效调节沟道层的铁磁性。我们的研究结果对于理解和实现高效基于 Ge 的自旋场效应晶体管具有重要的基础性意义。
