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arXiv · 2510.18954

Haerter-Shastry kinetic magnetism and metallicity in the triangular Hubbard model

Sogoud Sherif·Prakash Sharma·Aman Kumar·Hitesh J. Changlani
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Abstract

The fermionic Hubbard model, when combined with the ingredient of frustration, associated with the breaking of particle-hole symmetry, harbors a rich phase diagram. Aspects of theoretical findings associated with the nature of magnetism and metallicity, in a diverse set of parameter regimes, are now being actively investigated in triangular Hubbard cold atom and solid-state (moir\'e) based emulators. Building on the theoretical work of Haerter and Shastry [Phys. Rev. Lett. 95,087202 (2005)], we explore the impact of kinetically frustrated magnetism, a phenomenon where antiferromagnetic order emerges without any underlying magnetic interactions, at finite hole density. We numerically study the infinite-$U$ triangular Hubbard model using the density matrix renormalization group algorithm and estimate the extent of stability of the kinetically induced $120^{\circ}$ antiferromagnetic state to hole doping. Beyond the Haerter-Shastry regime, we find an intermediate phase with multimer (involving multiple correlated spins) stripes that eventually gives way to a paramagnet. We also find evidence of gapless charge excitations (metallicity) throughout the phase diagram for finite hole density. We discuss the implications at large, but finite and realistic values of $U/t$, and investigate whether kinetic magnetism and superexchange collaborate or compete.

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Sogoud Sherif, Prakash Sharma, Aman Kumar, Hitesh J. Changlani. 2025-10-21. Haerter-Shastry kinetic magnetism and metallicity in the triangular Hubbard model. https://arxiv.org/abs/2510.18954

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