Anomalous Normal Fluid Response in Chiral Superconductor UTe2
Seokjin Bae, Hyunsoo Kim, Yun S. Eo, Nicholas Butch, Sheng Ran
A chiral superconductor has been proposed as one pathway to realize topological quantum computation utilizing the predicted Majorana normal fluid at its boundary11-4 (i.e., a point, edge, or surface). The search for experimental realizations has led to the discovery of 1D5 and 2D6 chiral superconducting systems. However, the long-sought 3D chiral superconductor with surface Majorana normal fluid is yet to be found. Here we report evidence for a chiral spin-triplet pairing state of UTe2 with significant surface normal fluid response. The microwave surface impedance of UTe2 crystals was measured and converted to complex conductivity. The anomalous residual normal fluid conductivity in the zero temperature limit supports the presence of a significant normal fluid response. The super fluid conductivity follows the low temperature behavior predicted for the chiral spin-triplet state. The temperature dependence of the super fluid conductivity also reveals a low impurity scattering rate and low frequency-to-energy-gap ratio, implying that the observed normal fluid response does not have a trivial origin. Our findings suggest that UTe2 can be a new platform to study exotic topological excitations in higher dimension, and may play the role of a versatile 3D building block in the future era of topological quantum computation.
, Kim, H.
, Eo, Y.
, Butch, N.
and Ran, S.
Anomalous Normal Fluid Response in Chiral Superconductor UTe<sub>2</sub>, Nature Communications, [online], https://doi.org/10.1038/s41467-021-22906-6
(Accessed February 27, 2024)