Topological phase interference induced by a magnetic field along hard anisotropy axis in nanospin systems with different crystal symmetries

2000 ◽  
Vol 61 (21) ◽  
pp. 14581-14591 ◽  
Author(s):  
Rong Lü ◽  
Hui Hu ◽  
Jia-Lin Zhu ◽  
Xiao-Bing Wang ◽  
Lee Chang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Anisotropy Axis ◽  
Topological Phase ◽  
Phase Interference

scholarly journals Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

2018 ◽  
Vol 9 ◽  
pp. 1512-1526 ◽  
Author(s):  
Tudor D Stanescu ◽  
Anna Sitek ◽  
Andrei Manolescu
Keyword(s):  
Magnetic Field ◽  
Longitudinal Magnetic Field ◽  
Tight Binding ◽  
Core Shell ◽  
Topological Phase ◽  
Binding Model ◽  
Chemical Potentials ◽  
Topological Quantum ◽  
The Stability ◽  
Shell Nanowires

We consider core–shell nanowires with prismatic geometry contacted with two or more superconductors in the presence of a magnetic field applied parallel to the wire. In this geometry, the lowest energy states are localized on the outer edges of the shell, which strongly inhibits the orbital effects of the longitudinal magnetic field that are detrimental to Majorana physics. Using a tight-binding model of coupled parallel chains, we calculate the topological phase diagram of the hybrid system in the presence of non-vanishing transverse potentials and finite relative phases between the parent superconductors. We show that having finite relative phases strongly enhances the stability of the induced topological superconductivity over a significant range of chemical potentials and reduces the value of the critical field associated with the topological quantum phase transition.

scholarly journals Experimental Observation of Temperature-Driven Topological Phase Transition in HgTe/CdHgTe Quantum Wells

2019 ◽  
Author(s):  
Maksim Zholudev ◽  
Aleksandr Kadykov ◽  
Mikhail Fadeev ◽  
Michal Marcinkiewicz ◽  
Sandra Ruffenach ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quantum Wells ◽  
Topological Insulator ◽  
Critical Magnetic Field ◽  
Topological Phase ◽  
Temperature Dependent ◽  
Transition Parameter ◽  
Topological Phase Transition ◽  
Band Insulator

We report on comparison between temperature-dependent magneto¬absorption and magnetotransport spectroscopy of HgTe/CdHgTe quantum wells in terms of detection of phase transition between topological insulator and band insulator states. Our results demonstrate that temperature-dependent magnetospectroscopy is a powerful tool to discriminate trivial and topological insulator phases, yet magnetotransport method is shown to have advantages for clear manifestation of the phase transition with accurate quantitative values of transition parameter (i.e. critical magnetic field Bc).

Bifurcations in the Dynamical System for Three-Layered Magnetic Valve

2015 ◽  
Vol 233-234 ◽  
pp. 431-434 ◽  
Author(s):  
Natalia Ostrovskaya ◽  
Vladimir Skidanov ◽  
Iuliia Iusipova
Keyword(s):  
Magnetic Field ◽  
Dynamical System ◽  
Nonlinear Dynamical System ◽  
Anisotropy Field ◽  
Anisotropy Axis ◽  
Magnetization Dynamics ◽  
Nonlinear Dynamical ◽  
Demagnetizing Field ◽  
Spin Polarized ◽  
Space Dependence

Magnetization dynamics in a three-layered nanopillar Co/Cu/Co structure with one fixed and one free layer driven by external magnetic field and spin-polarized electric current was investigated using methods of the theory of bifurcations. Mathematical model is based on the Landau-Lifshits-Gilbert equation with the current term in the Sloncžewski–Berger form. Orientation of applied magnetic field was considered to be parallel to the anisotropy axis. Physical model included the magnetocrystalline anisotropy field and the demagnetizing field. Because of small size of the structure, the space dependence of magnetization, as usually, was not taken into account. The resulting system of equations has the form of the nonlinear dynamical system with the polynomial right sides. Mathematical simulation of magnetization dynamics for several typical values of field and current was performed. The numerical experiments revealed the features of switching process in more detail and permitted to find new regimes of magnetization dynamics, such as incomplete and accidental switching.

scholarly journals Experimental Observation of Temperature-Driven Topological Phase Transition in HgTe/CdHgTe Quantum Wells

2019 ◽  
Vol 4 (1) ◽  
pp. 27 ◽  
Author(s):  
Maksim S. Zholudev ◽  
Aleksandr M. Kadykov ◽  
Mikhail A. Fadeev ◽  
Michal Marcinkiewicz ◽  
Sandra Ruffenach ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quantum Wells ◽  
Topological Insulator ◽  
Critical Magnetic Field ◽  
Topological Phase ◽  
Temperature Dependent ◽  
Transition Parameter ◽  
Topological Phase Transition ◽  
Band Insulator

We report on the comparison between temperature-dependent magneto-absorption and magnetotransport spectroscopy of HgTe/CdHgTe quantum wells in terms of the detection of the phase transition between the topological insulator and band insulator states. Our results demonstrate that temperature-dependent magnetospectroscopy is a powerful tool to discriminate trivial and topological insulator phases, yet the magnetotransport method is shown to have advantages for the clear manifestation of the phase transition with accurate quantitative values of the transition parameter (i.e., critical magnetic field Bc).

scholarly journals Topological valley currents via ballistic edge modes in graphene superlattices near the primary Dirac point

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Yang Li ◽  
Mario Amado ◽  
Timo Hyart ◽  
Grzegorz. P. Mazur ◽  
Jason W. A. Robinson
Keyword(s):  
Magnetic Field ◽  
Boron Nitride ◽  
Dirac Point ◽  
Hexagonal Boron Nitride ◽  
Zero Magnetic Field ◽  
Decay Length ◽  
Topological Phase ◽  
Show Evidence ◽  
Nonlocal Transport

AbstractGraphene on hexagonal boron nitride (hBN) can exhibit a topological phase via mutual crystallographic alignment. Recent measurements of nonlocal resistance (Rnl) near the secondary Dirac point (SDP) in ballistic graphene/hBN superlattices have been interpreted as arising due to the quantum valley Hall state. We report hBN/graphene/hBN superlattices in which Rnl at SDP is negligible, but below 60 K approaches the value of h/2e2 in zero magnetic field at the primary Dirac point with a characteristic decay length of 2 μm. Furthermore, nonlocal transport transmission probabilities based on the Landauer-Büttiker formalism show evidence for spin-degenerate ballistic valley-helical edge modes, which are key for the development of valleytronics.

Sign in / Sign up

Export Citation Format

Share Document