Efficient gate control of spin–orbit interaction in InSb nanowire FET with a nearby back gate

Abstract

Electrical tuning of spin–orbit interaction (SOI) is important for spintronics. Here we report that InSb nanowire with a nearby back gate structure enables efficient tuning of the Rashba SOI with small gate voltage. Consequently, the Rashba coupling parameter is larger than those obtained for various previously reported III–V nanowire devices. Our findings demonstrate that InSb nanowire with this back gate structure will provide prominent and easy-to-use devices in the fields of spintronics and spin–orbitronics.

Improved effective equation for the Rashba spin-orbit coupling in semiconductor nanowires

“…We note that the material with the largest SO coupling is InSb, which is roughly twice that of InAs, as it was pointed out in previous works [37,64]. This is due to the small band gap and large split-off gap that characterizes InSb.…”

“…During the last decade, there has been an increasing interest in measuring the SO coupling in semiconductor nanowires due to their potential applications as spin-FETs [25][26][27][61][62][63] or Majorana qubit devices [41,42]. In most cases, these nanowires were made of InAs due to its large semiconductor band gap and Rashba coupling, although some of them used InSb nanowires [59,64] and other mixed heterostructures [65][66][67][68][69][70][71][72] involving type III-V compound semiconductors. For the comparison, we focus on the works done by Dhara et al [62], Liang et al [25], Takase et al [27], and Scherübl et al [26], carried out on zinc-blende InAs nanowires; and by Takase et al [64] on zinc-blende InSb nanowires.…”

“…In most cases, these nanowires were made of InAs due to its large semiconductor band gap and Rashba coupling, although some of them used InSb nanowires [59,64] and other mixed heterostructures [65][66][67][68][69][70][71][72] involving type III-V compound semiconductors. For the comparison, we focus on the works done by Dhara et al [62], Liang et al [25], Takase et al [27], and Scherübl et al [26], carried out on zinc-blende InAs nanowires; and by Takase et al [64] on zinc-blende InSb nanowires. We choose these experiments because they measure a representative number of SO coupling points versus a wide range of gate potentials.…”

“…They prove that it is possible to enhance the Rashba coupling by using an appropriate electrostatic environment. [26], and (e) Takase et al [64]. The charge density of the wire is taken into account in the Thomas-Fermi approximation and the surface charge is ρ surf = 5 × 10 −3 ( e nm 3 ).…”

“…Finally, Fig. 5(e) refers to the experiment realized by Takase et al [64] in InSb nanowires. This work proves that the SO coupling of InSb nanowires is much larger than that of InAs ones.…”