Quantum Hall states observed in thin films of Dirac semimetal Cd3As2

• Published in: Nature communications Vol. 8; no. 1; pp. 1 - 2274
• Main Authors: Uchida, Masaki, Nakazawa, Yusuke, Nishihaya, Shinichi, Akiba, Kazuto, Kriener, Markus, Kozuka, Yusuke, Miyake, Atsushi, Taguchi, Yasujiro, Tokunaga, Masashi, Nagaosa, Naoto, Tokura, Yoshinori, Kawasaki, Masashi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22.12.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 147/143; 639/301/119/2792; 639/301/119/544; 639/766/119/995; Electronic structure; Film thickness; Hall effect; Humanities and Social Sciences; multidisciplinary; Quantum Hall effect; Quantum theory; Quantum transport; Science; Science (multidisciplinary); Splitting; Thin films; Transport phenomena
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02423-1

A well known semiconductor Cd 3 As 2 has reentered the spotlight due to its unique electronic structure and quantum transport phenomena as a topological Dirac semimetal. For elucidating and controlling its topological quantum state, high-quality Cd 3 As 2 thin films have been highly desired. Here we report the development of an elaborate growth technique of high-crystallinity and high-mobility Cd 3 As 2 films with controlled thicknesses and the observation of quantum Hall effect dependent on the film thickness. With decreasing the film thickness to 10 nm, the quantum Hall states exhibit variations such as a change in the spin degeneracy reflecting the Dirac dispersion with a large Fermi velocity. Details of the electronic structure including subband splitting and gap opening are identified from the quantum transport depending on the confinement thickness, suggesting the presence of a two-dimensional topological insulating phase. The demonstration of quantum Hall states in our high-quality Cd 3 As 2 films paves a road to study quantum transport and device application in topological Dirac semimetal and its derivative phases. Despite many achievements in the topological semimetal Cd 3 As 2 , the high-quality Cd 3 As 2 films are still rare. Here, Uchida et al. grow high-crystallinity and high-mobility Cd 3 As 2 thin films and observe quantum Hall states dependent on the confinement thickness.