## 摘要

We report the Drude oscillator strength D and the magnitude of the bulk band gap Eg of the epitaxially grown, topological insulator (Bi,Sb)2Te3. The magnitude of Eg, in conjunction with the model independent f-sum rule, allows us to establish an upper bound for the magnitude of D expected in a typical Dirac-like system composed of linear bands. The experimentally observed D is found to be at or below this theoretical upper bound, demonstrating the effectiveness of alloying in eliminating bulk charge carriers. Moreover, direct comparison of the measured D to magnetoresistance measurements of the same sample supports assignment of the observed low-energy conduction to topological surface states.

原文 | English |
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文章編號 | 116804 |

期刊 | Physical Review Letters |

卷 | 115 |

發行號 | 11 |

DOIs | |

出版狀態 | Published - 11 九月 2015 |