Inducing a metal-insulator transition in disordered interacting Dirac fermion systems via an external magnetic field

We investigate metal-insulator transitions on an interacting two-dimensional Dirac fermion system using the determinant quantum Monte Carlo method. The interplay between Coulomb repulsion, disorder and magnetic fields, drives the otherwise semi-metallic regime to insulating phases exhibiting differe...

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Bibliographic Details
Published in:arXiv.org 2021-07
Main Authors: Meng, Jingyao, Mondaini, Rubem, Ma, Tianxing, Hai-Qing Lin
Format: Article
Language:English
Subjects:
Electron spin
Fermions
Insulators
Magnetic fields
Metal-insulator transition
Monte Carlo simulation
Polarization (spin alignment)
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Summary:We investigate metal-insulator transitions on an interacting two-dimensional Dirac fermion system using the determinant quantum Monte Carlo method. The interplay between Coulomb repulsion, disorder and magnetic fields, drives the otherwise semi-metallic regime to insulating phases exhibiting different characters. In particular, with the focus on the transport mechanisms, we uncover that their combination exhibits dichotomic effects. On the one hand, the critical Zeeman field \(B_c\), responsible for triggering the band-insulating phase due to spin-polarization on the carriers, is largely reduced by the presence of the electronic interaction and quenched disorder. On the other hand, the insertion of a magnetic field induces a more effective localization of the fermions, facilitating the onset of Mott or Anderson insulating phases. Yet these occur at moderate values of \(B\), and cannot be explained by the full spin-polarization of the electrons.
ISSN:2331-8422
DOI:10.48550/arxiv.2104.05387