Tuning Rashba spin-orbit coupling in homogeneous semiconductor nanowires

Wójcik, P.; Bertoni, Alberto; Goldoni, Guido

doi:10.1103/physrevb.97.165401

Cited by 39 publications

(43 citation statements)

References 59 publications

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“…This is due to the different effects on the charge density, as discussed in Ref. 5. This effect can also be grasped from the probability distribution reported in Fig.…”

supporting

confidence: 65%

“…Until polygonal symmetry holds, α R = 0 regardless. However, external gates easily remove the symmetry; again, how α R moves from zero under the influence of the external gates strongly depends on the charge density regime 5 .…”

mentioning

confidence: 99%

“…The used k · p approach is described in full in Ref. 5; here we focus on generalizations required to account for the contribution of the internal heterointerface. The 8 × 8 Kane Hamiltonian is given by 16…”

mentioning

confidence: 99%

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Enhanced Rashba spin-orbit coupling in core-shell nanowires by the interfacial effect

Wójcik

Bertoni

Goldoni

2019

Applied Physics Letters

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We report on k · p calculations of Rashba spin-orbit coupling controlled by external gates in InAs/InAsP core-shell nanowires. We show that charge spilling in the barrier material allows for a stronger symmetry breaking than in homoegenous nano-materials, inducing a specific interface-related contribution to spin-orbit coupling. Our results qualitatively agree with recent experiments [S. Futhemeier et al., Nat. Commun. 7, 12413 (2016)] and suggest additional wavefunction engineering strategies to enhance and control spin-orbit coupling.

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“…This is due to the different effects on the charge density, as discussed in Ref. 5. This effect can also be grasped from the probability distribution reported in Fig.…”

supporting

confidence: 65%

mentioning

confidence: 99%

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Enhanced Rashba spin-orbit coupling in core-shell nanowires by the interfacial effect

Wójcik

Bertoni

Goldoni

2019

Applied Physics Letters

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“…For instance, the electrostatic profile is not homogeneous along (and across) the wire, which creates a position-dependent chemical potential 23,24,26,[41][42][43] that has consequences for the topological phase transition and the shape and the overlap of MBSs [44][45][46][47] . It also creates a position-dependent Rashba spin-orbit coupling [48][49][50] . Moreover, the charge density is not distributed uniformly across the wire and its location depends strongly on the external gate voltage 49,51 .…”

Section: Introductionmentioning

confidence: 99%

Effects of the electrostatic environment on superlattice Majorana nanowires

et al. 2019

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Finding ways of creating, measuring and manipulating Majorana bound states (MBSs) in superconducting-semiconducting nanowires is a highly pursued goal in condensed matter physics. It was recently proposed that a periodic covering of the semiconducting nanowire with superconductor fingers would allow both gating and tuning the system into a topological phase while leaving room for a local detection of the MBS wavefunction. We perform a detailed, self-consistent numerical study of a three-dimensional (3D) model for a finite-length nanowire with a superconductor superlattice including the effect of the surrounding electrostatic environment, and taking into account the surface charge created at the semiconductor surface. We consider different experimental scenarios where the superlattice is on top or at the bottom of the nanowire with respect to a back gate. The analysis of the 3D electrostatic profile, the charge density, the low energy spectrum and the formation of MBSs reveals a rich phenomenology that depends on the nanowire parameters as well as on the superlattice dimensions and the external back gate potential. The 3D environment turns out to be essential to correctly capture and understand the phase diagram of the system and the parameter regions where topological superconductivity is established. * Corresponding author: elsa.prada@uam.es 1 M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 3045

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“…On the other hand, spin-orbit coupling is expected to be small, compared to the energy gaps of tens of meV which we obtain in multi-particle spectra, and the intensities of optical transitions forbidden by spin selection rules in our calculations will be considerably weaker than the spin-conserving ones. A quantitative estimation of spin-orbit coupling in core-shell nanowires is beyond the scope of this work [58,59]. Now, we focus on the three excitonic states of zone IV, which correspond to spin singlet configuration, with the conduction electron and vacancy localized on the same corner, Fig.…”

Section: Excitations Lifetimementioning

confidence: 99%

Excitons in Core–Shell Nanowires with Polygonal Cross Sections

et al. 2018

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The distinctive prismatic geometry of semiconductor core-shell nanowires leads to complex localization patterns of carriers. Here, we describe the formation of optically active in-gap excitonic states induced by the interplay between localization of carriers in the corners and their mutual Coulomb interaction. To compute the energy spectra and configurations of excitons created in the conductive shell, we use a multi-electron numerical approach based on the exact solution of the multi-particle Hamiltonian for electrons in the valence and conduction bands, which includes the Coulomb interaction in a nonperturbative manner. We expose the formation of well separated quasidegenerate levels, and focus on the implications of the electron localization in the corners or on the sides of triangular, square and hexagonal cross sections. We obtain excitonic in-gap states associated with symmetrically distributed electrons in the spin singlet configuration. They acquire large contributions due to Coulomb interaction, and thus are shifted to much higher energies than other states corresponding to the conduction electron and the vacancy localized in the same corner. We compare the results of the multi-electron method with those of an electron-hole model and we show that the latter does not reproduce the singlet excitonic states. We also obtain the exciton lifetime and explain selection rules which govern the recombination process.

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Tuning Rashba spin-orbit coupling in homogeneous semiconductor nanowires

Cited by 39 publications

References 59 publications

Enhanced Rashba spin-orbit coupling in core-shell nanowires by the interfacial effect

Enhanced Rashba spin-orbit coupling in core-shell nanowires by the interfacial effect

Effects of the electrostatic environment on superlattice Majorana nanowires

Excitons in Core–Shell Nanowires with Polygonal Cross Sections

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