Fabrication of a novel magnetic topological heterostructure and temperature evolution of its massive Dirac cone.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32973165.
- Also identified by DOI 10.1038/s41467-020-18645-9 and PMC identifier 7515900.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 Mn<sub>4</sub>Bi<sub>2</sub>Te<sub>7</sub>/Bi<sub>2</sub>Te<sub>3</sub> where multiple magnetic layers are inserted into the topmost quintuple layer of the original topological insulator Bi<sub>2</sub>Te<sub>3</sub>. 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 MnBi<sub>2</sub>Te<sub>4</sub>/Bi<sub>2</sub>Te<sub>3</sub>. Magnetic measurements show that there are two distinct Mn components in the system that corresponds to the two heterostructures; MnBi<sub>2</sub>Te<sub>4</sub>/Bi<sub>2</sub>Te<sub>3</sub> is paramagnetic at 6 K while Mn<sub>4</sub>Bi<sub>2</sub>Te<sub>7</sub>/Bi<sub>2</sub>Te<sub>3</sub> is ferromagnetic with a negative hysteresis (critical temperature ~20 K). This novel heterostructure is potentially important for future device applications.