Odd-parity surface magnetism in a Kondo insulator
Abstract
We formulate a theory of spin-polarized tunneling between a nanowire tip of a topological Kondo insulator SmB6 and the bi-collinear antiferromagnet Fe1+xTe in which the tunneling conductance which measures magnetic contrast changes sign when the bias is reversed. First we show that no time-reversal-symmetric tip, however strong its spin-momentum locking is, can produce experimentally observed magnetic contrast, which implies that time reversal must be broken at the tip surface. Within a mean-field treatment of the surface theory of SmB6 we find that the interaction between conduction d- and f-electrons drives a surface phase transition near Tc≈10 K in which the time-reversal-odd component of the Kondo hybridization amplitude condenses in the same symmetry channel as an out-of-plane surface magnetization, gapping out the Dirac surface states. Below the transition the spin-resolved spectral function of each gapped surface Dirac cone is odd in energy about its node. For a charge-neutral apex the Fermi level lies between the surface Γ̅ and X̅ Dirac nodes, so the spin-polarized conductance, which is determined by this function at the bias energy, reverses its sign close to zero bias. This sign change is thus a spectroscopic signature of time-reversal symmetry breaking on the surface of SmB6.
Related
- Spin-polarized tunneling from a Kondo insulator: equilibrium surface magnetism versus magneto-electric response in SmB6
- Anisotropic Surface State Band Splitting and Low Energy Flat Bands in 3d Correlated Topological Kondo Insulator Candidate FeSb2
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- Persistent Photo-Enhancement of Molecular Orbital Excitations in the Kondo Insulator FeSb2
- Topological Chiral Superconductivity from Doping Correlated Charge Transfer Insulator with Orbital Magnetism
BibTeX
@misc{dzero2026oddparity,
title = {{Odd-parity surface magnetism in a Kondo insulator}},
author = {Maxim Dzero and Brian M. Andersen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.12573},
eprint = {2610.12573},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.12573},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Odd-parity surface magnetism in a Kondo insulator
AU - Maxim Dzero
AU - Brian M. Andersen
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.12573
UR - https://arxiv.org/abs/2610.12573
AB - We formulate a theory of spin-polarized tunneling between a nanowire tip of a topological Kondo insulator SmB_6 and the bi-collinear antiferromagnet Fe_1+xTe in which the tunneling conductance which measures magnetic contrast changes sign when the bias is reversed. First we show that no time-reversal-symmetric tip, however strong its spin-momentum locking is, can produce experimentally observed magnetic contrast, which implies that time reversal must be broken at the tip surface. Within a mean-field treatment of the surface theory of SmB_6 we find that the interaction between conduction d- and f-electrons drives a surface phase transition near T_c≈10 K in which the time-reversal-odd component of the Kondo hybridization amplitude condenses in the same symmetry channel as an out-of-plane surface magnetization, gapping out the Dirac surface states. Below the transition the spin-resolved spectral function of each gapped surface Dirac cone is odd in energy about its node. For a charge-neutral apex the Fermi level lies between the surface Γ̅ and X̅ Dirac nodes, so the spin-polarized conductance, which is determined by this function at the bias energy, reverses its sign close to zero bias. This sign change is thus a spectroscopic signature of time-reversal symmetry breaking on the surface of SmB_6.
ER -