Unconventional superconductivity in weakly correlated, non-centrosymmetric $\rm{Mo_3Al_2C}$

E. Bauer; G. Rogl; Xing-Qiu Chen; R. T. Khan; H. Michor; G. Hilscher; E. Royanian; K. Kumagai; D. Z. Li; Y. Y. Li; R. Podloucky; P. Rogl

doi:10.1103/physrevb.82.064511

arXiv · 1007.0420

Unconventional superconductivity in weakly correlated, non-centrosymmetric $\rm{Mo_3Al_2C}$

E. Bauer·G. Rogl·Xing-Qiu Chen·R. T. Khan·H. Michor·G. Hilscher·E. Royanian·K. Kumagai·D. Z. Li·Y. Y. Li·R. Podloucky·P. Rogl

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Abstract

Electrical resistivity, specific heat and NMR measurements classify non-centrosymmetric $\rm Mo_3Al_2C$ ($\beta$-Mn type, space group $P4_132$) as a strong-coupled superconductor with $T_c = 9$~K deviating notably from BCS-like behaviour. The absence of a Hebbel-Slichter peak, a power law behaviour of the spin-lattice relaxation rate (from $^{27}$Al NMR), a $T^3$ temperature dependence of the specific heat and a pressure enhanced $T_c$ suggest unconventional superconductivity with a nodal structure of the superconducting gap. Relativistic DFT calculations reveal a splitting of degenerate electronic bands due to the asymmetric spin-orbit coupling, favouring a mix of spin-singlet and spin triplet components in the superconducting condensate, in absence of strong correlations among electrons.

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E. Bauer, G. Rogl, Xing-Qiu Chen, R. T. Khan, H. Michor, G. Hilscher, E. Royanian, K. Kumagai, D. Z. Li, Y. Y. Li, R. Podloucky, P. Rogl. 2010-07-02. Unconventional superconductivity in weakly correlated, non-centrosymmetric $\rm{Mo_3Al_2C}$. https://doi.org/10.1103/physrevb.82.064511

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