Strong Tuning of Rashba Spin–Orbit Interaction in Single InAs Nanowires

Abstract

A key concept in the emerging field of spintronics is the gate voltage or electric field control of spin precession via the effective magnetic field generated by the Rashba spin orbit interaction. Here, we demonstrate the generation and tuning of electric field induced Rashba spin orbit interaction in InAs nanowires where a strong electric field is created either by a double gate or a solid electrolyte surrounding gate. In particular, the electrolyte gating enables six-fold tuning of Rashba coefficient and nearly three orders of magnitude tuning of spin relaxation time within only 1 V of gate bias. Such a dramatic tuning of spin orbit interaction in nanowires may have implications in nanowire based spintronic devices.Nanowires of small band gap III-V semiconductors such as indium arsenide (InAs) have recently attracted significant interest in nanoelectronic device research.1-10 With high electron mobility, nanostructures of InAs have appealing potential for high speed electronics such as field effect transistor (FET). [3][4][5][6][7][8] In addition to high electron mobility that is important for charge transport based electronic devices, InAs also has strong spin-orbit interaction (SOI) and was proposed to be an essential material for spintronic devices such as spin FET in which controlling the electrons' spin degree of freedom renders the device's functionality. 11-13 Therefore, InAs nanowire appears to be also an interesting quasi-one dimensional (1D) platform to explore spintronic devices such as 1D spin-FET which exploits the SOI effect to control electrons' spin. SOI is a relativistic effect experienced by electrons (or any charge particles) moving in an electric field E. In the rest frame of the electron, E is Lorentz transformed into an effective magnetic field which couples to the electron's spin and consequently induces spin precession and relaxation. The electric field in this SOI effect could be from the asymmetry in the intrinsic crystal structure, the asymmetric confinement potential in heterostructure interface, or simply an externally applied

Magnetoconductance correction in zinc-blende semiconductor nanowires with spin-orbit coupling

“…[15][16][17][18], the variation of the dephasing length l φ with the gate voltage in the according fits is most striking. In most of these works, the dephasing length increases with the gate voltage which is usually justified by a reduced electron-electron interaction through an increase of the electron density.…”

“…[15][16][17][18]. We attribute this to the fact that even for zero gate voltage an intrinsic electric field due to Fermi level surface pinning will remain.…”

“…In disordered systems, the conductivity is either enhanced or reduced due to quantum interference, which is denoted as weak antilocalization (WAL) or weak localization (WL), respectively. By fitting the experimental data with an appropriate theoretical model, it is possible to extract SOC strengths as well as dephasing, scattering, and, most prominently, spin relaxation rates [9][10][11][12][13][14][15][16][17][18]. Notably, a crossover from WAL to WL can even indicate spin-preserving symmetries [19][20][21].…”

Near-thermal limit gating in heavily doped III-V semiconductor nanowires using polymer electrolytes

“…The resulting strong gating has seen electrolyte gating become a well-known approach to improved performance in materials ranging from organic semiconductors to chalcogenides [16]. Electrolyte gating also provides a simpler route to achieving concentric gating action for nanowire devices [13,17]. The key result of this work is a demonstration that electrolyte-gated nanowire transistors remain functional even in the limit where the doping density becomes sufficiently high that traditional gating approaches fail.…”

“…Additionally, PE gates are far simpler to produce than traditional metal-oxide wrap-gate structures [18][19][20][21] and utilise an intrinsically biocompatible material [22]. Nanopatterned PE gates have been used in applications from enacting external ionic doping of quantum devices [17,23] to ionic-to-electronic signal transduction [14]. Here we extend this to include improved p-type NWFETs for room temperature nanowire complementary circuits.…”