TY - JOUR
T1 - Converting topological insulators into topological metals within the tetradymite family
AU - Chen, K. W.
AU - Aryal, N.
AU - Dai, J.
AU - Graf, D.
AU - Zhang, S.
AU - Das, S.
AU - Le Fèvre, P.
AU - Bertran, F.
AU - Yukawa, R.
AU - Horiba, K.
AU - Kumigashira, H.
AU - Frantzeskakis, E.
AU - Fortuna, F.
AU - Balicas, L.
AU - Santander-Syro, A. F.
AU - Manousakis, E.
AU - Baumbach, R. E.
N1 - Funding Information:
This work was performed at the National High Magnetic Field Laboratory (NHMFL), which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490, the State of Florida and the DOE. A portion of this work was supported by the NHMFL User Collaboration Grant Program (UCGP). L.B. is supported by DOE-BES through award DE-SC0002613. The work at KEK-PF was performed under the approval of the Program Advisory Committee (proposals 2016G621 and 2015S2-005) at the Institute of Materials Structure Science. K.-W.C. and N.A. contributed equally to this work.
Funding Information:
This work was performed at the National High Magnetic Field Laboratory (NHMFL), which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490, the State of Florida and the DOE. A portion of this work was supported by the NHMFL User Collaboration Grant Program (UCGP). L.B. is supported by DOE-BES through award DE-SC0002613. The work at KEK-PF was performed under the approval of the Program Advisory Committee (proposals 2016G621 and 2015S2-005) at the Institute of Materials Structure Science.
Publisher Copyright:
© 2018 American Physical Society.
PY - 2018/4/9
Y1 - 2018/4/9
N2 - We report the electronic band structures and concomitant Fermi surfaces for a family of exfoliable tetradymite compounds with the formula T2Ch2Pn, obtained as a modification to the well-known topological insulator binaries Bi2(Se,Te)3 by replacing one chalcogen (Ch) with a pnictogen (Pn) and Bi with the tetravalent transition metals T= Ti, Zr, or Hf. This imbalances the electron count and results in layered metals characterized by relatively high carrier mobilities and bulk two-dimensional Fermi surfaces whose topography is well-described by first-principles calculations. Intriguingly, slab electronic structure calculations predict Dirac-like surface states. In contrast to Bi2Se3, where the surface Dirac bands are at the Γ point, for (Zr,Hf)2Te2(P,As) there are Dirac cones of strong topological character around both the Γ and M points, which are above and below the Fermi energy, respectively. For Ti2Te2P, the surface state is predicted to exist only around the M point. In agreement with these predictions, the surface states that are located below the Fermi energy are observed by angle-resolved photoemission spectroscopy measurements, revealing that they coexist with the bulk metallic state. Thus this family of materials provides a foundation upon which to develop novel phenomena that exploit both the bulk and surface states (e.g., topological superconductivity).
AB - We report the electronic band structures and concomitant Fermi surfaces for a family of exfoliable tetradymite compounds with the formula T2Ch2Pn, obtained as a modification to the well-known topological insulator binaries Bi2(Se,Te)3 by replacing one chalcogen (Ch) with a pnictogen (Pn) and Bi with the tetravalent transition metals T= Ti, Zr, or Hf. This imbalances the electron count and results in layered metals characterized by relatively high carrier mobilities and bulk two-dimensional Fermi surfaces whose topography is well-described by first-principles calculations. Intriguingly, slab electronic structure calculations predict Dirac-like surface states. In contrast to Bi2Se3, where the surface Dirac bands are at the Γ point, for (Zr,Hf)2Te2(P,As) there are Dirac cones of strong topological character around both the Γ and M points, which are above and below the Fermi energy, respectively. For Ti2Te2P, the surface state is predicted to exist only around the M point. In agreement with these predictions, the surface states that are located below the Fermi energy are observed by angle-resolved photoemission spectroscopy measurements, revealing that they coexist with the bulk metallic state. Thus this family of materials provides a foundation upon which to develop novel phenomena that exploit both the bulk and surface states (e.g., topological superconductivity).
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U2 - 10.1103/PhysRevB.97.165112
DO - 10.1103/PhysRevB.97.165112
M3 - Article
AN - SCOPUS:85045145431
VL - 97
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 16
M1 - 165112
ER -