Role of hybridization and magnetic effects in massive Dirac cones: Magnetic topological heterostructures with controlled film thickness

Abstract

We fabricated MnBi2Se4/(n − 1) quintuple layer (QL) Bi2Se3 magnetic topological heterostructures (n = 1–6) and measured the Dirac cone dispersion with angle-resolved photoemission spectroscopy. We observed a clear gap opening for films with n = 2–6 and the gap size decreased as the film thickness increased. From magnetization measurements using SQUID, all the heterostructures showed hysteresis loops at 4 K and at room temperature, confirming that MnBi2Se4 is a room temperature van der Waals ferromagnet. We were able to distinguish the contribution of the hybridization and magnetic effects on the observed Dirac-cone gap directly using a four-band model and its implications on the behavior of the expected quantum anomalous Hall effect is discussed.

Axion insulator state in ferromagnetically ordered CrI3/Bi2Se3/MnBHou1, Kim2, Wu3 2020Phys. Rev. B262190View full textAdd to dashboardCite

“…MBS SL has already been synthesized by δ-doping BS [26,48], and 2) CI 3 /BS can be mechanically assembled owing to their vdW nature [49,50]. A practical scheme of growing of CrI 3 /BS/MBS is sketched in Fig.…”

“…The MBS SL can be first synthesized on a suitable substrate following the methods of Ref. [26,48]. BS films can then be grown it through molecular-beam epitaxy [47].…”

Carrier Density and Thickness Dependent Proximity Effect in Doped Topological Insulator -- Metallic Ferromagnet Bilayers

“…Magnetic fields normal to the surface will open a gap at the Dirac points 1,2 . Magnetically gapped surface states host a variety of fascinating phenomena, including the quantum anomalous Hall effect (QAHE) 7,8 .…”

“…One way to break TRS is by interfacing a TI with a ferromagnetic (FM) material [7][8][9][10][11][12][13][14][15] . The surface states interact with the magnetic moments and acquire a magnetic proximity effect induced energy gap 7,8,14 .…”

“…One way to break TRS is by interfacing a TI with a ferromagnetic (FM) material [7][8][9][10][11][12][13][14][15] . The surface states interact with the magnetic moments and acquire a magnetic proximity effect induced energy gap 7,8,14 . One major advantage of this method is the ability to pattern the FM layer and create spatially varying magnetic interactions 6 .…”