Theory of Spin Exciton in the Kondo Semiconductor $Yb{B}_{12}$

Abstract

The Kondo semiconductor $Yb{B}_{12}$ exhibits a spin and charge gap of approximately 15 meV. Close to the gap energy narrow dispersive collective excitations were identified by previous inelastic neutron scattering experiments. We present a theoretical analysis of these excitations. Starting from a periodic Anderson model for crystalline electric field (CEF) split 4f states we derive the hybridized quasiparticle bands in slave boson mean-field approximation and calculate the momentum dependent dynamical susceptibility in random phase approximation (RPA). We show that a small difference in the hybridization of the two CEF (quasi-) quartets leads to the appearance of two dispersive spin resonance excitations at the continuum threshold. Their intensity is largest at the antiferromagnetic (AF) zone boundary point and they have an upward dispersion which merges with the continuum less than halfway into the Brillouin zone. Our theoretical analysis explains the most salient features of previously unexplained experiments on the magnetic excitations of $Yb{B}_{12}$.

arXiv comment5 pages, 4 figures, To be published in Physical Review Letters

References in corpus (4)

• Feedback spin resonance in superconducting CeCu${}_2$Si${}_2$ and CeCoIn${}_5$
• Evidence for short-range antiferromagnetic fluctuations in Kondo-insulating YbB12
• Indirect and direct energy gaps in the Kondo semiconductor YbB12
• Yb-Yb correlations and crystal-field effects in the Kondo insulator YbB12 and its solid solutions

Cited by in corpus (13)

• Momentum-Dependent Hybridization Gap and dispersive in-gap state of The Kondo Semiconductor SmB6
• Spin Exciton Formation inside the Hidden Order Phase of CeB6
• Hall anomaly, Quantum Oscillations and Possible Lifshitz Transitions in Kondo Insulator YbB${}_{12}$: Evidence for Unconventional Charge Transport
• Field induced spin exciton doublet splitting in d_{x^2-y^2}-wave 115-heavy electron superconductors
• Quantum spin fluctuations in the bulk insulating state of pure and Fe-doped SmB6
• Discontinuous Transition from a Real Bound State to Virtual Bound State in a Mixed-Valence State of SmS
• Crystal field potential and short-range order effects in inelastic neutron scattering, magnetization and heat capacity of the cage-glass compound HoB12
• Collective spin resonance excitation in the gapped itinerant multipole hidden order phase of URu2Si2
• Heavy quasiparticle bands in the underscreened quasiquartet Kondo lattice
• Optical and magnetic excitations in the underscreened quasi-quartet Kondo lattice
• Crystalline electric field excitations in Weyl semimetal \textit{R}AlSi (\textit{R} = Ce, Pr and Nd)
• Singlet-triplet Hamiltonian for spin excitation in the Kondo-insulator
• Insulator-to-metal phase transition in Yb-based Kondo insulators