Spin-Selective Spectral Flattening and Wave-Packet Dynamics in a Flux-Engineered Lieb Lattice
Abstract
We investigate reversible internal-state-selective wave-packet transport induced by spin-dependent Peierls phases in a two-dimensional nearest-neighbor Lieb lattice. The two conserved spin components experience effective fluxes ασ=α0+sσαs, where s↑,↓=±1. At the working point α0=αs=1/4, the spin-up and spin-down components experience α↑=1/2 and α↓=0, respectively. A band-resolved calculation in the q=2 magnetic unit cell shows that the spin-up spectrum contains two zero-energy flat subbands associated with the sublattice-imbalance flat-band sector, whereas the remaining four subbands retain finite bandwidths. The half-flux sector therefore fails the all-bands-flat condition and does not realize exact Aharonov--Bohm caging for a generic localized initial state. Nevertheless, real-time simulations reveal a pronounced suppression of spin-up propagation relative to the dispersive spin-down component, manifested by a smaller mean-square displacement and an enhanced finite-region retention probability over the pre-reflection time window. Reversing the state-dependent flux interchanges the slow and fast spin channels, while the dynamical contrast remains robust against moderate flux detuning. These results establish spin-dependent synthetic flux as a reversible means of controlling internal-state-resolved matter-wave transport without spin-flip processes or interactions, and provide complementary spectral and real-space criteria for distinguishing exact caging from finite-time dynamical slowing in atomic and photonic flat-band simulators.
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BibTeX
@misc{chang2026spinselective,
title = {{Spin-Selective Spectral Flattening and Wave-Packet Dynamics in a Flux-Engineered Lieb Lattice}},
author = {Nana Chang and Xiaoji Zhou and Yanglin Zhou and Song Ci},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.28054},
eprint = {2608.28054},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.28054},
}
RIS
TY - UNPB
TI - Spin-Selective Spectral Flattening and Wave-Packet Dynamics in a Flux-Engineered Lieb Lattice
AU - Nana Chang
AU - Xiaoji Zhou
AU - Yanglin Zhou
AU - Song Ci
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2608.28054
UR - https://arxiv.org/abs/2608.28054
AB - We investigate reversible internal-state-selective wave-packet transport induced by spin-dependent Peierls phases in a two-dimensional nearest-neighbor Lieb lattice. The two conserved spin components experience effective fluxes α_σ=α_0+s_σα_s, where s_↑,↓=±1. At the working point α_0=α_s=1/4, the spin-up and spin-down components experience α_↑=1/2 and α_↓=0, respectively. A band-resolved calculation in the q=2 magnetic unit cell shows that the spin-up spectrum contains two zero-energy flat subbands associated with the sublattice-imbalance flat-band sector, whereas the remaining four subbands retain finite bandwidths. The half-flux sector therefore fails the all-bands-flat condition and does not realize exact Aharonov--Bohm caging for a generic localized initial state. Nevertheless, real-time simulations reveal a pronounced suppression of spin-up propagation relative to the dispersive spin-down component, manifested by a smaller mean-square displacement and an enhanced finite-region retention probability over the pre-reflection time window. Reversing the state-dependent flux interchanges the slow and fast spin channels, while the dynamical contrast remains robust against moderate flux detuning. These results establish spin-dependent synthetic flux as a reversible means of controlling internal-state-resolved matter-wave transport without spin-flip processes or interactions, and provide complementary spectral and real-space criteria for distinguishing exact caging from finite-time dynamical slowing in atomic and photonic flat-band simulators.
ER -