TY - JOUR
T1 - Differences in Chemical Doping Matter
T2 - Superconductivity in Ti1-xTaxSe2 but Not in Ti1-xNbxSe2
AU - Luo, Huixia
AU - Xie, Weiwei
AU - Tao, Jing
AU - Pletikosic, Ivo
AU - Valla, Tonica
AU - Sahasrabudhe, Girija S.
AU - Osterhoudt, Gavin
AU - Sutton, Erin
AU - Burch, Kenneth S.
AU - Seibel, Elizabeth M.
AU - Krizan, Jason W.
AU - Zhu, Yimei
AU - Cava, Robert J.
N1 - Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/3/22
Y1 - 2016/3/22
N2 - We report that 1T-TiSe2, an archetypical layered transition metal dichalcogenide, becomes superconducting when Ta is substituted for Ti but not when Nb is substituted for Ti. This is unexpected because Nb and Ta should be chemically equivalent electron donors. Superconductivity emerges near x = 0.02 for Ti1-xTaxSe2, while, for Ti1-xNbxSe2, no superconducting transitions are observed above 0.4 K. The equivalent chemical nature of the dopants is confirmed by X-ray photoelectron spectroscopy. ARPES and Raman scattering studies show similarities and differences between the two systems, but the fundamental reasons why the Nb and Ta dopants yield such different behavior are unknown. We present a comparison of the electronic phase diagrams of many electron-doped 1T-TiSe2 systems, showing that they behave quite differently, which may have broad implications in the search for new superconductors. We propose that superconducting Ti0.8Ta0.2Se2 will be suitable for devices and other studies based on exfoliated crystal flakes.
AB - We report that 1T-TiSe2, an archetypical layered transition metal dichalcogenide, becomes superconducting when Ta is substituted for Ti but not when Nb is substituted for Ti. This is unexpected because Nb and Ta should be chemically equivalent electron donors. Superconductivity emerges near x = 0.02 for Ti1-xTaxSe2, while, for Ti1-xNbxSe2, no superconducting transitions are observed above 0.4 K. The equivalent chemical nature of the dopants is confirmed by X-ray photoelectron spectroscopy. ARPES and Raman scattering studies show similarities and differences between the two systems, but the fundamental reasons why the Nb and Ta dopants yield such different behavior are unknown. We present a comparison of the electronic phase diagrams of many electron-doped 1T-TiSe2 systems, showing that they behave quite differently, which may have broad implications in the search for new superconductors. We propose that superconducting Ti0.8Ta0.2Se2 will be suitable for devices and other studies based on exfoliated crystal flakes.
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U2 - 10.1021/acs.chemmater.6b00288
DO - 10.1021/acs.chemmater.6b00288
M3 - Article
AN - SCOPUS:84962119061
SN - 0897-4756
VL - 28
SP - 1927
EP - 1935
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 6
ER -