Spiral phases and two-particle bound states from a systematic low-energy effective theory for magnons, electrons, and holes in an antiferromagnet
✍ Scribed by C. Brügger; C.P. Hofmann; F. Kämpfer; M. Pepe; U.-J. Wiese
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 161 KB
- Volume
- 403
- Category
- Article
- ISSN
- 0921-4526
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✦ Synopsis
We have constructed a systematic low-energy effective theory for hole-and electron-doped antiferromagnets, where holes reside in momentum space pockets centered at ðAEp=2a; AEp=2aÞ and where electrons live in pockets centered at ðp=a; 0Þ or ð0; p=aÞ. 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 Schro¨dinger equation. As a result, we find bound state wave functions that resemble d x 2 Ày 2 -like or d xy -like symmetry. We also study possible ground states of lightly doped antiferromagnets.