PC-1-4

Quantum critically in nitrogen vacancy doped SmN?

11:15-11:30　28/11/2023

*W. F. Holmes-Hewett, K. Van Koughnet, J. D. Miller, E. X. M. Trewick, B. J. Ruck, H. J. Trodahl and R. G. Buckley
The MacDiarmid Institute
for Advanced Materials and Nanotechnology and Robinson Research Institute, Victoria University of Wellington,
PO Box 600, Wellington 6140, New Zealand
The MacDiarmid Institute
for Advanced Materials and Nanotechnology and The School of Chemical and Physical Sciences, Victoria University of Wellington,
PO Box 600, Wellington 6140, New Zealand
Abstract Body

We investigate the previously observed superconductivity in ferromagnetic SmN [1] in the context of the breakdown of order between two magnetic phases [2]. Nitrogen vacancy doped SmN is a semiconductor which lies in the intermediary between ferromagnetic SmN and anti-ferromagnetic Sm. Optical data reported here corroborate the prediction that electrical transport is mediated by Sm 4f defect states [3,4], and electrical transport measurements characterise the metal-insulator transition over the doping range. Our measurements show that the superconducting state in nitrogen vacancy doped SmN is the most robust near the breakdown of magnetic order, and indicate the location of a quantum critical point. Furthermore we provide additional evidence that the superconducting state is formed from majority spin electrons and thus of unconventional S=1 type.

References

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[2] Coleman P, Schofield AJ. Quantum criticality. Nature. 2005 Jan 20;433(7023):226-9.
[3] W. F. Holmes-Hewett Phys. Rev. B 104, 075124, 2021.
[4] W. F. Holmes-Hewett, F. H. Ullstad, B. J. Ruck, F. Natali, and H. J. Trodahl, Phys. Rev. B 98, 235201, 2018.