Presentation Information
[PCP1-04]Electronic Structure of New Superconductor Rh1-xPtxSb with NiAs Structure
*Izumi Hase1, Akira Iyo1, Yoichi Higashi1, Kenji Kawashima1,2 (1. National Institute of Advanced Industrial Science and Technology (AIST) (Japan), 2. IMRA-JAPAN Co. Ltd. (Japan))
Keywords:
superconductivity,NiAs-type structure,first-principles calculation,virtual crystal approximation
[Purpose] 3d NiAs-type compounds have long been studied, and the close relationship between magnetism and structural phase transitions (NiAs-type ↔ MnP-type) has attracted attention. However, there has been little research on NiAs-type compounds in the 4d and 5d systems. Therefore, we investigate the 4d and 5d NiAs-type compounds and found a new series of superconductors, Rh1-xPtxSb. In order to understand the superconducting properties, we performed a first-principles calculation for Rh1-xPtxSb.
[Method] We calculated the electronic band structure of Rh1-xPtxSb by using virtual crystal approximation. As for the end members RhSb, PtSb, and also PdSb, we also calculated the phonon dispersion for investigating the stability of NiAs structure.
[Results] First we confirmed that the band structures of PtSb and PdSb are very look alike. Then we calculated the electronic structure of Rh1-xPdxSb by using a virtual crystal approximation. Next, we obtained the density of states at the Fermi level for each Pt-content x. Combining the experimentally obtained Debye temperature for each Pt-content x, we semi-quantitatively reproduced experimental Tc by the BCS theory.
As for the structural instability, we found that NiAs-structure is stable for PtSb and PdSb, while it is unstable for RhSb.
[Consideration] Our calculation shows that the x-dependence of Tc can be semi-quantitatively by the BCS theory with using the virtual crystal approximation. This result is consistent with the experimental finding that the superconducting properties of this system such as superconducting gap and penetration depth obey the BCS theory.
[Conclusion] We calculated the electronic structure of new superconductor Rh1-xPtxSb with NiAs-type structure. We found that the x-dependence of Tc can be semi-quantitatively reproduced combining the BCS theory and the virtual crystal approximation. This result not only shows the effectiveness of the virtual crystal approximation for this alloy system, but also suggests the mechanism of the superconductivity of this system to be the BCS theory.
[Method] We calculated the electronic band structure of Rh1-xPtxSb by using virtual crystal approximation. As for the end members RhSb, PtSb, and also PdSb, we also calculated the phonon dispersion for investigating the stability of NiAs structure.
[Results] First we confirmed that the band structures of PtSb and PdSb are very look alike. Then we calculated the electronic structure of Rh1-xPdxSb by using a virtual crystal approximation. Next, we obtained the density of states at the Fermi level for each Pt-content x. Combining the experimentally obtained Debye temperature for each Pt-content x, we semi-quantitatively reproduced experimental Tc by the BCS theory.
As for the structural instability, we found that NiAs-structure is stable for PtSb and PdSb, while it is unstable for RhSb.
[Consideration] Our calculation shows that the x-dependence of Tc can be semi-quantitatively by the BCS theory with using the virtual crystal approximation. This result is consistent with the experimental finding that the superconducting properties of this system such as superconducting gap and penetration depth obey the BCS theory.
[Conclusion] We calculated the electronic structure of new superconductor Rh1-xPtxSb with NiAs-type structure. We found that the x-dependence of Tc can be semi-quantitatively reproduced combining the BCS theory and the virtual crystal approximation. This result not only shows the effectiveness of the virtual crystal approximation for this alloy system, but also suggests the mechanism of the superconductivity of this system to be the BCS theory.