Abstract
The 3-layer rhombohedral (3R) polytype of TaSe2-xTex is known to display a superconducting transition temperature that is between 6 and 17 times higher than that of the two-layer hexagonal (2H) polytype. The remarkable difference in T c, although clearly associated with a difference in polytype, could have been due to an electronic effect specific to the Te-Se substitution. Here we report that small amounts of Mo or W doping lead to a 2H to 3R polytype transition in Ta1-xMoxSe2 and Ta1-xWxSe2. The 3R polytype materials are again found to have substantially higher T c (∼2 K for Ta0.9W0.1Se2 and Ta0.9Mo0.1Se2) than the 2H material (0.15 K), eliminating the possibility that any special characteristics of the Te/Se substitution are responsible for the dramatic difference in T c. We infer that a three-layer stacking sequence is strongly preferred for superconductivity over a two-layer stacking sequence in the TaSe2 system.
Original language | English (US) |
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Article number | 365701 |
Journal | Journal of Physics Condensed Matter |
Volume | 27 |
Issue number | 36 |
DOIs | |
State | Published - Sep 16 2015 |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- General Materials Science
Keywords
- 3R-polytype
- layered dichalcogenides
- superconductivity