Fabrication of a novel magnetic topological heterostructure and temperature evolution of its massive Dirac cone.

ABSTRACT: Materials that possess nontrivial topology and magnetism is known to exhibit exotic quantum phenomena such as the quantum anomalous Hall effect. Here, we fabricate a novel magnetic topological heterostructure Mn₄Bi₂Te₇/Bi₂Te₃ where multiple magnetic layers are inserted into the topmost quintuple layer of the original topological insulator Bi₂Te₃. A massive Dirac cone (DC) with a gap of 40-75?meV at 16?K is observed. By tracing the temperature evolution, this gap is shown to gradually decrease with increasing temperature and a blunt transition from a massive to a massless DC occurs around 200-250?K. Structural analysis shows that the samples also contain MnBi₂Te₄/Bi₂Te₃. Magnetic measurements show that there are two distinct Mn components in the system that corresponds to the two heterostructures; MnBi₂Te₄/Bi₂Te₃ is paramagnetic at 6?K while Mn₄Bi₂Te₇/Bi₂Te₃ is ferromagnetic with a negative hysteresis (critical temperature  ~20?K). This novel heterostructure is potentially important for future device applications.

SUBMITTER: Hirahara T 

PROVIDER: S-EPMC7515900 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature