Direct observation of multiple conduction-band minima in high-performance thermoelectric SnSe

Mario Okawa*, Yuka Akabane, Mizuki Maeda, Gangjian Tan, Li Dong Zhao, Mercouri G. Kanatzidis, Takeshi Suzuki, Mari Watanabe, Jiadi Xu, Qianhui Ren, Masami Fujisawa, Teruto Kanai, Jiro Itatani, Shik Shin, Kozo Okazaki, Naurang L. Saini, Takashi Mizokawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We report time- and angle-resolved photoemission spectroscopy on SnSe which currently attracts great interest due to its extremely high thermoelectric performance. Laser-assisted photoemission signals are observed within ±20 fs of the pump pulse arrival. Around 30–50 fs after the photoexcitation, the conduction band minima are not populated by the photoexcited electrons while the valence bands are considerably broadened. In going from 90 fs to 550 fs after the photoexcitation, the photoexcited carriers are decayed into the multiple conduction band minima. The observed conduction bands are consistent with the band structure calculations. The multiple conduction minima suggest possibility of high and anisotropic thermoelectric performance of n-type SnSe single crystal if it is realized.

Original languageEnglish
Article number115081
JournalScripta Materialia
Volume223
DOIs
Publication statusPublished - 2023 Jan 15

Keywords

  • Angle-resolved photoemission sepctroscopy (ARPES)
  • Dynamic phenomena
  • Electronic structure
  • Semiconductor
  • Thermoelectric materials

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys

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