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arXiv · 2202.04374

Metal-insulator transition in a boundary three chain model

Niels John·Yuval Gefen·Bernd Rosenow
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Abstract

We study the boundary physics of bulk insulators by considering three coupled Hubbard chains in a linear confining potential. In the Hartree-Fock approximation, the ground state at and slightly off the particle-hole symmetric point remains insulating even at large slopes of the confining potential. By contrast, accounting for quantum fluctuations and correlations through a combination of bosonization and RG methods, we find that there is always a gapless dipole mode, but it does not contribute to a finite compressibility. Moreover, when increasing the slope of the confining potential at half filling, we find a quantum phase transition between an insulating and a metallic state, indicating the formation of a soft edge state of non-topological origin. Away from half filling, a similar transition takes place.

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Niels John, Yuval Gefen, Bernd Rosenow. 2022-02-09. Metal-insulator transition in a boundary three chain model. https://arxiv.org/abs/2202.04374

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