https://doi.org/10.1140/epjb/e2015-60175-5
Regular Article
Giant magnetoresistance of edge current between fermion and spin topological systems
G.V. Kurdyumov Institute for Metal Physics,
N.A.S. of Ukraine, 36 Vernadsky
Boulevard, 03142
Kiev,
Ukraine
a e-mail: igor.slieptsov@mail.com
Received:
5
March
2015
Received in final form:
1
May
2015
Published online:
13
July
2015
A spin-½ subsystem conjoined along a cut with a subsystem of spinless fermions in the state of topological insulator is studied on a honeycomb lattice. The model describes a junction between a 2D topological insulator and a 2D spin lattice with direction-dependent exchange interactions in topologically trivial and nontrivial phase states. The model Hamiltonian of the complex system is solved exactly by reduction to free Majorana fermions in a static Z2 gauge field. In contrast to junctions between topologically trivial phases, this junction is defined by chiral edge states and direct interaction between them for topologically nontrivial phases. As a result of the boundary interaction between chiral edge modes, the edge junction is defined by the Chern numbers of the subsystems: such gapless edge modes with the same (different) chirality switch on (off) an edge current between topological subsystems. The sign of the Chern number of spin subsystem is changed in an external magnetic field, thus the electric current strongly depends both on a direction and a value of an applied weak magnetic field. We provide a detailed analysis of the edge current and demonstrate how to switch on (off) the electric current in the magnetic field.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2015