Correlated quantum criticality and topological magnetoelectric response in Bi2Se3
Abstract
A defining feature of quantum materials is that multiple orders govern low-energy physics and are not independent. We study Bi2Se3 by combining DFT with a renormalized correlated honeycomb model in which frustrated magnetic order and helical topological surface states are coupled via one control parameter. The surface states map to a honeycomb Hubbard model with frustrated J1--J2 exchange. Exact diagonalization up to 20 sites shows the Néel structure factor and valence-bond-solid order parameter cross at J2/J1 ≈ 0.22, agreeing with QMC/DMRG, and a dynamical spin structure factor broadens near the crossover, as expected for a spinon continuum. Band inversion of the renormalized tight-binding model occurs on the same critical locus, producing jumps in the Chern number and ℤ2 invariant mirrored by the skyrmion charge Q. This gives a microscopic link: Q selects the axion angle and thus the topological magnetoelectric coupling. We distinguish axion coupling, independent of skyrmion helicity, from the helicity-dependent magnetoelectric multipole coupling, whose toroidal component scales as sinγ and vanishes for Néel-type textures. We derive the Q-topological magnetoelectric energy and estimate ∼ 10−20 J per skyrmion per cycle for few-tesla fields. The cycle is thermodynamically bounded: constant-θ cycles extract no net work, and efficiency is limited by axionic entropy change.
Related
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- Toward Quantum Utility in Correlated Topological Matter: Variational Preparation of Fractional Quantum Hall Manifolds
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- Correlation-Driven Nonlinear Magnetoelectric Response in an Altermagnet: A Dynamical Mean-Field Study
- Spin response of a magnetic monopole and quantum Hall response in topological lattice models through local invariants and light
BibTeX
@misc{ukpong2026correlated,
title = {{Correlated quantum criticality and topological magnetoelectric response in Bi2Se3}},
author = {Aniekan Magnus Ukpong},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.03670},
eprint = {2611.03670},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.03670},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Correlated quantum criticality and topological magnetoelectric response in Bi2Se3
AU - Aniekan Magnus Ukpong
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.03670
UR - https://arxiv.org/abs/2611.03670
AB - A defining feature of quantum materials is that multiple orders govern low-energy physics and are not independent. We study Bi_2Se_3 by combining DFT with a renormalized correlated honeycomb model in which frustrated magnetic order and helical topological surface states are coupled via one control parameter. The surface states map to a honeycomb Hubbard model with frustrated J_1--J_2 exchange. Exact diagonalization up to 20 sites shows the Néel structure factor and valence-bond-solid order parameter cross at J_2/J_1 ≈ 0.22, agreeing with QMC/DMRG, and a dynamical spin structure factor broadens near the crossover, as expected for a spinon continuum. Band inversion of the renormalized tight-binding model occurs on the same critical locus, producing jumps in the Chern number and ℤ_2 invariant mirrored by the skyrmion charge Q. This gives a microscopic link: Q selects the axion angle and thus the topological magnetoelectric coupling. We distinguish axion coupling, independent of skyrmion helicity, from the helicity-dependent magnetoelectric multipole coupling, whose toroidal component scales as sinγ and vanishes for Néel-type textures. We derive the Q-topological magnetoelectric energy and estimate ∼ 10^−20 J per skyrmion per cycle for few-tesla fields. The cycle is thermodynamically bounded: constant-θ cycles extract no net work, and efficiency is limited by axionic entropy change.
ER -