Topological superconductivity in tripartite superconductor-ferromagnet-semiconductor nanowires

Langbehn, Josias; González, Sergio Acero; Brouwer, Piet W.; Oppen, Felix von

doi:10.1103/physrevb.103.165301

Cited by 19 publications

(12 citation statements)

References 35 publications

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“…[20][21][22][23], the relative positioning of the ferromagnetic and superconducting layers on top of the nanowire could affect the electrostatic potential profile inside the semiconductor as well as the total strength of the induced Zeeman spin splitting in a delicate manner. Additionally, it has also been shown via a phenomenological model that topological superconductivity can appear in a hybrid system when the ferromagnetic film is inserted as a spin-filtering barrier separating the semiconductor and superconductor layers [24,25]. The advantage of such a proposal using ferromagnetic spinfiltering layer is the generic applicability to both quasione-dimensional nanowire and two-dimensional-electrongas systems.…”

Section: Introductionmentioning

confidence: 99%

Optimizing the topological properties of stacking semiconductor-ferromagnet-superconductor heterostructures

Liu,

Wimmer

2022

Preprint

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We study the electronic properties of a planar semiconductor-superconductor heterostructure, in which a thin ferromagnetic insulator layer lies in between and acts as a spin filtering barrier. We find that in such a system one can simultaneously enhance the strengths of all the three important induced physical quantities, i.e., Rashba spin-orbit coupling, exchange coupling, and superconducting pairing potential, for the hybrid mode by external gating. Our results show specific advantage of this stacked device geometry compared to conventional devices. We further discuss how to optimize geometrical parameters for the heterostructure and complement our numerical simulations with analytic calculations.

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Section: Introductionmentioning

confidence: 99%

Optimizing the topological properties of stacking semiconductor-ferromagnet-superconductor heterostructures

Liu,

Wimmer

2022

Preprint

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“…With the aforementioned on one hand, the basic Rashba wire setup has further drawbacks which includes the requirement of large magnetic fields that could potentially destroy superconductivity [37][38][39][40] apart from the practicalities of precise magnetic field alignment [41]. Recently, efforts are being made towards realizing * bm@ee.iitb.ac.in topological superconductivity with zero external magnetic fields by using proximity effects from magnetic insulators (MI) [42][43][44][45][46][47][48][49][50][51][52]. Recent experimental [43] and theoretical works [44][45][46][47][48]51] featuring this setup indicate that at very low external magnetic fields, or even zero external magnetic fields, a topological MZM phase can emerge.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, efforts are being made towards realizing * bm@ee.iitb.ac.in topological superconductivity with zero external magnetic fields by using proximity effects from magnetic insulators (MI) [42][43][44][45][46][47][48][49][50][51][52]. Recent experimental [43] and theoretical works [44][45][46][47][48]51] featuring this setup indicate that at very low external magnetic fields, or even zero external magnetic fields, a topological MZM phase can emerge. The object of this paper is hence to provide an in-depth analysis of the transport signatures of MZMs in these structures, particularly focusing on the local and non-local conductance spectra in both pristine and disordered nanowires.…”

Section: Introductionmentioning

confidence: 99%

Conductance Spectroscopy of Majorana Zero Modes in Superconductor-Magnetic Insulating Nanowire Hybrid Systems

Singh¹,

Muralidharan²

2022

Preprint

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There has been a recent interest in superconductor-magnetic insulator hybrid Rashba nanowire setups for potentially hosting Majorana zero modes at smaller external Zeeman fields. Using the Keldysh non-equilibrium Green's function technique, we develop a detailed quantum transport approach that accounts for the hybrid structure comprising the Rashba nanowire coupled to the bilayer structure which includes the proximity inducing superconductor and the magnetic insulator. We provide a detailed analysis of three terminal setups to probe the local and non-local conductance spectra in both the pristine as well as the disordered nanowire setups. We uncover the conductance quantization scaling with the bilayer coupling and the signatures of the gap closing followed by the emergence of near-zero energy states, which can be attributed to topological zero modes in the clean limit. However, in the presence of a smoothly varying disorder potential, trivial Andreev bound states may form with signatures reminiscent of topological zero modes in the form of a premature gap closure in the non-local conductance spectra. Our results therefore provide transport-based analysis of the operating regimes that support the formation of Majorana modes in these hybrid systems of current interest, while investigating the effect of disorder on experimentally relevant device structures.

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“…Another class imagines shells of magnetic insulators on nanowires as a path to topological superconductivity through using exchange interactions [19,20]. These results have sparked a debate about the feasibility and true origin of the observed signals [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Integrating micromagnets and hybrid nanowires for topological quantum computing

et al. 2021

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Majorana zero modes are expected to arise in semiconductor-superconductor hybrid systems, with potential topological quantum computing applications. One limitation of this approach is the need for a relatively high external magnetic field that should also change direction at the nanoscale. This proposal considers devices that incorporate micromagnets to address this challenge. We perform numerical simulations of stray magnetic fields from different micromagnet configurations, which are then used to solve for Majorana wavefunctions. Several devices are proposed, starting with the basic four-magnet design to align magnetic field with the nanowire and scaling up to nanowire T-junctions. The feasibility of the approach is assessed by performing magnetic imaging of prototype patterns.

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Topological superconductivity in tripartite superconductor-ferromagnet-semiconductor nanowires

Cited by 19 publications

References 35 publications

Optimizing the topological properties of stacking semiconductor-ferromagnet-superconductor heterostructures

Optimizing the topological properties of stacking semiconductor-ferromagnet-superconductor heterostructures

Conductance Spectroscopy of Majorana Zero Modes in Superconductor-Magnetic Insulating Nanowire Hybrid Systems

Integrating micromagnets and hybrid nanowires for topological quantum computing

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