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arXiv · 0706.1423

Spiral phases and two-particle bound states from a systematic low-energy effective theory for magnons, electrons, and holes in an antiferromagnet

C. Brügger·C. P. Hofmann·F. Kämpfer·M. Moser·M. Pepe·U. -J. Wiese
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Abstract

We have constructed a systematic low-energy effective theory for hole- and electron-doped antiferromagnets, where holes reside in momentum space pockets centered at $(\pm\fracπ{2a},\pm\fracπ{2a})$ and where electrons live in pockets centered at $(\fracπ{a},0)$ or $(0,\fracπ{a})$. The effective theory is used to investigate the magnon-mediated binding between two holes or two electrons in an otherwise undoped system. We derive the one-magnon exchange potential from the effective theory and then solve the corresponding two-quasiparticle Schrödinger equation. As a result, we find bound state wave functions that resemble $d_{x^2-y^2}$-like or $d_{xy}$-like symmetry. We also study possible ground states of lightly doped antiferromagnets.

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C. Brügger, C. P. Hofmann, F. Kämpfer, M. Moser, M. Pepe, U. -J. Wiese. 2007-06-11. Spiral phases and two-particle bound states from a systematic low-energy effective theory for magnons, electrons, and holes in an antiferromagnet. https://doi.org/10.1016/j.physb.2007.10.168

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