Vyasanakere, Jayantha P and Shenoy, Vijay B (2012) Rashbons: properties and their significance. In: NEW JOURNAL OF PHYSICS, 14 .
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Abstract
In the presence of a synthetic non-Abelian gauge field that produces a Rashba-like spin-orbit interaction, a collection of weakly interacting fermions undergoes a crossover from a Bardeen-Cooper-Schrieffer (BCS) ground state to a Bose-Einstein condensate (BEC) ground state when the strength of the gauge field is increased (Vyasanakere et al 2011 Phys. Rev. B 84 014512). The BEC that is obtained at large gauge coupling strengths is a condensate of tightly bound bosonic fermion pairs. The properties of these bosons are solely determined by the Rashba gauge field-hence called rashbons. In this paper, we conduct a systematic study of the properties of rashbons and their dispersion. This study reveals a new qualitative aspect of the problem of interacting fermions in non-Abelian gauge fields, i.e. that the rashbon state ceases to exist when the center-of-mass momentum of the fermions exceeds a critical value that is of the order of the gauge coupling strength. The study allows us to estimate the transition temperature of the rashbon BEC and suggests a route to enhance the exponentially small transition temperature of the system with a fixed weak attraction to the order of the Fermi temperature by tuning the strength of the non-Abelian gauge field. The nature of the rashbon dispersion, and in particular the absence of the rashbon states at large momenta, suggests a regime in parameter space where the normal state of the system will be a dynamical mixture of uncondensed rashbons and unpaired helical fermions. Such a state should show many novel features including pseudogap physics.
Item Type: | Journal Article |
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Publication: | NEW JOURNAL OF PHYSICS |
Publisher: | IOP PUBLISHING LTD |
Additional Information: | Copyright for this article belongs to Thomson Reuters |
Keywords: | SUPERCONDUCTIVITY;ATOMS |
Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
Date Deposited: | 10 Jul 2012 07:17 |
Last Modified: | 10 Jul 2012 07:20 |
URI: | http://eprints.iisc.ac.in/id/eprint/44601 |
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