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Evolution of the Fermi Surface of a Doped Topological Insulator With Carrier Concentration


  E. Maniv [1]  ,  E. Lahoud [2]  ,  M. Shaviv Petrushevsky [1]  ,  M. Naamneh [2]  ,  A. Ribak [2]  ,  S. Wiedmann [3]  ,  L. Petaccia [4]  ,  Z. Salman [5]  ,  K. B. Chashka [2]  ,  Amit Kanigel [2]  ,  Yoram Dagan [1]  
 [1] Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel Aviv, 69978, Israel
[2] Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
[3] High Field Magnet Laboratory, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7,NL-6525 ED Nijmegen, The Netherlands
[4] Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149 Trieste, Italy
[5] Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland

In an ideal bulk topological-insulator (TI) conducting surface states protected by time reversal symmetry enfold an insulating crystal. However, the archetypical TI, Bi2Se3 , is actually never insulating; it is in fact a relatively good metal. Nevertheless, it is the most studied system among all the TIs, mainly due to its simple band-structure and large spin-orbit gap. Recently it was shown that copper intercalated Bi2Se3 becomes superconducting and it was suggested as a realization of a topological superconductor (TSC). Here we use a combination of techniques that are sensitive to the shape of the Fermi surface (FS): the Shubnikov-de Haas (SdH) effect and angle resolved photoemission spectroscopy (ARPES) to study the evolution of the FS shape with carrier concentration, n. We find that as n increases, the FS becomes 2D-like. These results are of crucial importance for understanding the superconducting properties of CuxBi2Se3.