Molecular Beam Epitaxy

21MBE Growth of Ge‐Based Diluted Magnetic Semiconductors

Tianxiao Nie^1,2, Jianshi Tang³ and Kang L. Wang²

¹Fert Beijing Institute, BDBC, and School of Electronic and Information Engineering, Beihang University, Beijing, 100191, China

²Device Research Laboratory, Department of Electrical Engineering, University of California, Los Angeles, CA 90095, USA

³IBM Thomas J. Watson Research Center, Yorktown Heights, NY 10598, USA

21.1 Introduction

The control of ferromagnetism has traditionally been accomplished by applying a current [1]. However, using an electric current poses a big challenge in reducing the power dissipation and scaling down the size of devices [ 1,2]. Recently, spin‐current has been widely used to manipulate the ferromagnetism through spin‐transfer torque (STT) [3–6] and spin‐orbit torque (SOT) [7–9], and one successful paradigm was its application in STT‐magnetic random access memory (MRAM) [10,11]. It has widely been considered as one of the most promising candidates for next‐generation non‐volatile memory with high density, fast processing speed, low power dissipation and infinite endurance. Although the standby power could be significantly reduced or even eliminated in STT‐MRAM, the dynamics power dissipation is still extremely large, in particular for applications in cache or logic‐in‐memory architecture where frequent writing of the memory bits takes place [12]. Therefore, the voltage control of ferromagnetism has always drawn attention, due to its potential for building ...