Enhancement of charge-neutral fermionic excitation near spin-flop transition\\ in magnetic Kondo material YbIr${}_3$Si${}_7$

Abstract

The new Kondo material YbIr${}_3$Si${}_7$, similar to other Kondo insulators, has been reported to exhibit charge-neutral fermionic excitations through measurements of specific heat and thermal conductivity at low temperatures. We performed ${}^{29}$Si-NMR on YbIr${}_3$Si${}_7$ to investigate the magnetic response of charge-neutral fermions from a microscopic perspective. In low magnetic fields parallel to the $c$ axis, a single NMR peak in the paramagnetic state splits into three peaks below $T_{\mathrm{N}}$. In contrast, only a slight shift of the single NMR peak was observed in high magnetic fields. This spectral change as a function of the $c$-axis magnetic field is interpreted as spin-flop transition, at which the magnetic moments oriented along the $c$ axis (AF-I phase) are rotated to the $ab$ plane with ferromagnetic component along the $c$-axis (AF-II phase). In the vicinity of the spin-flop magnetic field $H_{\mathrm{M}}$, nuclear spin-lattice relaxation rate $1/T_1$ was found to be proportional to temperature at low temperatures, indicating the existence of charge-neutral fermions. Furthermore, a peak of $1/T_1$ vs. the $c$-axis magnetic field suggests that the charge-neutral fermions in YbIr${}_3$Si${}_7$ are closely related to its magnetic properties. Our findings shed light on the origin of charge-neutral fermions in insulators.

arXiv comment5 pages, 3 figures

References in corpus (16)

• Quantum Orders and Symmetric Spin Liquids
• Evidence for a spinon Fermi surface in a triangular lattice quantum spin liquid candidate
• Quantum oscillations in Kondo Insulator SmB${}_6$
• Quantum Oscillations of Electrical Resistivity in an Insulator
• Fermi surface in the absence of a Fermi liquid in the Kondo insulator SmB${}_6$
• Possible itinerant excitations and quantum spin state transitions in the effective spin-1/2 triangular-lattice antiferromagnet Na${}_2$BaCo(PO${}_4$)${}_2$
• Phase Diagram and Spin Dynamics in Volborthite with a Distorted Kagome Lattice
• Mixed-valence insulators with neutral Fermi surfaces
• Skyrme insulators: insulators at the brink of superconductivity
• Coexisting localized and itinerant gapless excitations in a quantum spin liquid candidate 1T-TaS${}_2$
• Unconventional thermal metallic state of charge-neutral fermions in an insulator
• Majoranas in mixed-valence insulators
• Field-Induced Instability of a Gapless Spin Liquid with a Spinon Fermi Surface
• Cyclotron resonance inside the Mott gap: a fingerprint of emergent neutral fermions
• Charge neutral fermions and magnetic field driven instability in insulating YbIr${}_3$Si${}_7$
• Cyclotron resonance in Kondo insulator

Cited by in corpus (1)

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