An unexpected charge doping mechanism for quasi-one-dimensional <i>A</i>Cr<sub>3</sub>As<sub>3</sub> superconductors
ORAL
Abstract
In the race to find topological materials, superconductivity has found renewed interest as potential hosts of Majorana Fermions. However, realizing such states is non-trivial requiring for instance Cooper pairs with finite orbital-momentum or Dirac-like dispersions in the normal state. Recently, a new family of quasi-1D superconductors A1,2Cr3As3 (A= Alkali metal) was discovered which is interesting in these regards for realizing spin-triplet superconductivity and having Dirac-like crossings near EF. However, its study has been hampered due to extreme air sensitivity and an inability to charge dope. Here, we report results of diffraction studies and DFT work on KCr3As3 which solve both these problems. We show that the reported growth technique inherently intercalates H into the quasi-1D CrAs tubes and that the H acts as an electron donor. Furthermore, we reveal that the reported discrepancy in sample behavior (with some superconducting and others spin-glasses) is actually due to the amount of H. This work suggests a new stoichiometry KH1-xCr3As3, which is air stable and provides a charge doping mechanism. This allows for tuning between frustrated magnetism and superconductivity in a quasi-1D material as well as a potential route to reach the predicted Dirac points.
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Presenters
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Keith Taddei
- Oak Ridge National Laboratory
- Oak Ridge National Lab
- Neutron Scattering Division, Oak Ridge National Laboratory
- HFIR, Oak Ridge National Laboratory