Structural and electronic phase transition in Bi2Se2.1Te0.9 under pressure

Yu Chin Tseng, Chih Ming Lin*, Sheng Rui Jian, Phuoc Huu Le, Marin M. Gospodinov, Vera Marinova, Dimitre Z. Dimitrov, Chih-Wei Luo, Kuang Hsiung Wu, Dong Zhou Zhang, Jenh Yih Juang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The phase evolution of Bi2Se2.1Te0.9 driven by the applied external pressure at ambient temperature was investigated in-situ with pressure up to 30.0(2) GPa using angle-dispersive X-ray diffraction (ADXRD) and Raman scattering spectroscopy. ADXRD measurements revealed that starting from the ambient rhombohedral structure (phase I), new forms of crystal structures are found to sequentially emerge with increasing externally applied pressure. Namely a seven-fold monoclinic structure (phase II), then an eight-fold monoclinic structure (phase III), a body-centered structure (BCC, phase IV), and finally a body-centered tetragonal structure (BCT, phase V) was observed at pressures of ~10.5(3) GPa, ~18.8(1) GPa, ~23.0(1) GPa, and ~28.0(2) GPa, respectively. The Raman scattering spectroscopy consistently showed that the pressures at which the corresponding phase appeared at ~10.2(2) GPa, ~18.9(1) GPa, and ~26.1(2) GPa, respectively. Moreover, the rhombohedral phase exhibited an even more pronounced signature of electronic topological transition in low-pressure regime, as compared with those previously observed in pristine Bi2Te3 and Bi2Se3. It appears that the alloying of Bi2Se3 with Bi2Te3 has led to more profound effects in the electronic and structural properties of the resultant system than that expected from the Vegard's law.

Original languageEnglish
Article number110123
JournalJournal of Physics and Chemistry of Solids
StatePublished - Sep 2021


  • Angle dispersive X-ray diffraction
  • Pressure-induced lectronic topological transition
  • Pressure-induced phase transition
  • Raman scattering
  • Topological insulators

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