Sum-Rule Constraints on the Surface State Conductance of Topological Insulators

被引:20
作者
Post, K. W. [1 ]
Chapler, B. C. [1 ]
Liu, M. K. [1 ]
Wu, J. S. [1 ]
Stinson, H. T. [1 ]
Goldflam, M. D. [1 ]
Richardella, A. R. [2 ]
Lee, J. S. [2 ]
Reijnders, A. A. [3 ,4 ]
Burch, K. S. [5 ]
Fogler, M. M. [1 ]
Samarth, N. [2 ]
Basov, D. N. [1 ]
机构
[1] Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA
[2] Penn State Univ, Dept Phys, University Pk, PA 16802 USA
[3] Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada
[4] Univ Toronto, Inst Opt Sci, Toronto, ON M5S 1A7, Canada
[5] Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA
基金
美国国家科学基金会;
关键词
SINGLE DIRAC CONE; TRANSPORT; GRAPHENE; DYNAMICS;
D O I
10.1103/PhysRevLett.115.116804
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
We report the Drude oscillator strength D and the magnitude of the bulk band gap E-g of the epitaxially grown, topological insulator (Bi, Sb)(2)Te-3. The magnitude of Eg, in conjunction with the model independent -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.
引用
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页数:5
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