Details

Autor(en) / Beteiligte

• Xi, Xiaoxiang
• Ma, Chunli
• Liu, Zhenxian
• Chen, Zhiqiang
• Ku, Wei
• Berger, H
• Martin, C
• Tanner, D B
• Carr, G L

Titel

Signatures of a pressure-induced topological quantum phase transition in BiTeI

Ist Teil von

• Physical review letters, 2013-10, Vol.111 (15), p.155701-155701, Article 155701

Ort / Verlag

United States

Erscheinungsjahr

2013

Quelle

American Physical Society

Beschreibungen/Notizen

• We report the observation of two signatures of a pressure-induced topological quantum phase transition in the polar semiconductor BiTeI using x-ray powder diffraction and infrared spectroscopy. The x-ray data confirm that BiTeI remains in its ambient-pressure structure up to 8 GPa. The lattice parameter ratio c/a shows a minimum between 2.0-2.9 GPa, indicating an enhanced c-axis bonding through p(z) band crossing as expected during the transition. Over the same pressure range, the infrared spectra reveal a maximum in the optical spectral weight of the charge carriers, reflecting the closing and reopening of the semiconducting band gap. Both of these features are characteristics of a topological quantum phase transition and are consistent with a recent theoretical proposal.