The 5th Special CMSM-ERATO Joint Seminar
(The 266th Special CMSM seminar)


Polymorphic changes with electrical and optical switching in MnTe semiconductor films

Dr. Shunsuke MORI 1,2
1 Department of Materials Science,
Graduate School of Engineering,
Tohoku University, Sendai, 980-8579, Japan
2 Present address: Astamuse company, ltd., Chiyoda-ku Tokyo,
101-0054, Japan
Date & Time: 15:00 - 16:00, April 30th (Tue), 2024.
Place: 2nd Conference Room, 1F, Main Bldg., Sengen site.

Abstract:

Manganese telluride (MnTe) is an interesting polymorphic semiconductor compound with different crystal structures depending on temperature. At room temperature, MnTe is well-known to exhibit a stable α phase (NiAs-type) with narrow bandgap, lower resistivity, and antiferromagnetic behaviors. α-MnTe has been widely studied in terms of spintronics [1], thermoelectric materials [2], and photonic applications [3]. Meanwhile, the α phase transforms into β (wurtzite-type) with an increase in temperature, showing different physical properties.
We have reported that MnTe with a melting-free polymorphic change, which are induced by Joule heating, can be used to realize a phase-change memory device that demonstrates a fast performance and low operation energy [4]. Moreover, these crystal structures and polymorphic changes have been successfully controlled by mechanical stress [5] or femtosecond-laser irradiation [6], opening the possibilities for various applications like straintronics and optoelectronics.
Moreover, our group has recently focused on the physical properties of these MnTe films such as electrical conduction mechanisms [7] and magnetic behaviors towards further applications.

References
[1] D. Kriegner et al., Nat. Commun. 7, 11623 (2016).
[2] Y. Xu et al., J. Mater. Chem. A 5, 19143 (2017).
[3] L. Li et al., Chem. Mater. 33, 338 (2021).
[4] S. Mori, S. Hatayama, Y. Shuang, D. Ando, Y. Sutou, Nat. Commun. 11, 85 (2020).
[5] S. Mori, Y. Wang, D. Ando, F. Narita, Y. Sutou, Materialia 24, 101493 (2022).
[6] S. Mori, H. Tanimura, T. Ichitsubo, Y. Sutou, ACS Appl. Mater. Interfaces 15, 42730–42736 (2023).
[7] M. Kim, S. Mori, Y. Shuang, S. Hatayama, D. Ando, Y. Sutou, Phys. Stat. Sol. – RRL 16, 2100641 (2022).

(Contact)

Ken-ichi Uchida, Spin Caloritronics Group
E-mail: UCHIDA.Kenichi[at]nims.go.jp