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Main Authors: Zhang, Zichong, Zhu, Shuze
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.12098
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author Zhang, Zichong
Zhu, Shuze
author_facet Zhang, Zichong
Zhu, Shuze
contents The exploration of quantum phenomena in complex materials such as moiré superlattices is limited by the O(N^3) scaling of conventional electronic structure methods. Here we introduce a high-performance tight-binding framework that reduces the complexity to O(N^1.5) by transforming the Hamiltonian into a real symmetric form and combining Sylvester's inertia law with LDL decomposition. This approach enables efficient band structure calculations for large systems: solving magic angle twisted bilayer graphene in minutes on a laptop and scaling to 1.5 million atoms within days on a workstation. We apply it to the previously inaccessible ultra-low twist-angle regime (less than 0.16 degree) with mechanical strain relaxation and find robust flat bands persisting down to 0.09 degree. Our framework bridges density functional theory accuracy with large-scale quantum simulation, opening a route to systematic data-driven exploration of mesoscale quantum materials.
format Preprint
id arxiv_https___arxiv_org_abs_2601_12098
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Efficient O(N^1.5) Electronic Structure Computation of Million-Atom Systems
Zhang, Zichong
Zhu, Shuze
Computational Physics
Mesoscale and Nanoscale Physics
The exploration of quantum phenomena in complex materials such as moiré superlattices is limited by the O(N^3) scaling of conventional electronic structure methods. Here we introduce a high-performance tight-binding framework that reduces the complexity to O(N^1.5) by transforming the Hamiltonian into a real symmetric form and combining Sylvester's inertia law with LDL decomposition. This approach enables efficient band structure calculations for large systems: solving magic angle twisted bilayer graphene in minutes on a laptop and scaling to 1.5 million atoms within days on a workstation. We apply it to the previously inaccessible ultra-low twist-angle regime (less than 0.16 degree) with mechanical strain relaxation and find robust flat bands persisting down to 0.09 degree. Our framework bridges density functional theory accuracy with large-scale quantum simulation, opening a route to systematic data-driven exploration of mesoscale quantum materials.
title Efficient O(N^1.5) Electronic Structure Computation of Million-Atom Systems
topic Computational Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2601.12098