We present a systematic study of the phase diagram of the t-t'-J model by using the Green's function Monte Carlo (GFMC) technique, implemented within the fixed-node (FN) approximation and a wave function that contains both antiferromagnetism and d-wave pairing. This enables us to study the interplay between these two kinds of order and compare the GFMC results with the ones obtained by the simple variational approach. By using a generalization of the forward-walking technique, we are able to calculate true FN ground-state expectation values of the pair-pair correlation functions. In the case of t'=0, there is a large region with a coexistence of superconductivity and antiferromagnetism that survives up to delta(c)similar to 0.10 for J/t=0.2, and delta(c)similar to 0.13 for J/t=0.4. The presence of a finite t'/t < 0 induces a strong suppression of both magnetic (with delta(c)less than or similar to 0.03 for J/t=0.2 and t'/t=-0.2) and pairing correlations. In particular, the latter ones are depressed both in the low-doping regime and around delta similar to 0.25, where strong size effects are present.

Magnetism and superconductivity in the t-t '-J model / Spanu, Leonardo; Lugas, Massimo; Becca, Federico; Sorella, Sandro. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 77:2(2008), pp. 024510.1-024510.9. [10.1103/PhysRevB.77.024510]

Magnetism and superconductivity in the t-t '-J model

Becca, Federico;Sorella, Sandro
2008-01-01

Abstract

We present a systematic study of the phase diagram of the t-t'-J model by using the Green's function Monte Carlo (GFMC) technique, implemented within the fixed-node (FN) approximation and a wave function that contains both antiferromagnetism and d-wave pairing. This enables us to study the interplay between these two kinds of order and compare the GFMC results with the ones obtained by the simple variational approach. By using a generalization of the forward-walking technique, we are able to calculate true FN ground-state expectation values of the pair-pair correlation functions. In the case of t'=0, there is a large region with a coexistence of superconductivity and antiferromagnetism that survives up to delta(c)similar to 0.10 for J/t=0.2, and delta(c)similar to 0.13 for J/t=0.4. The presence of a finite t'/t < 0 induces a strong suppression of both magnetic (with delta(c)less than or similar to 0.03 for J/t=0.2 and t'/t=-0.2) and pairing correlations. In particular, the latter ones are depressed both in the low-doping regime and around delta similar to 0.25, where strong size effects are present.
2008
77
2
1
9
024510
http://link.aps.org/doi/10.1103/PhysRevB.77.024510
https://arxiv.org/abs/0709.2850
Spanu, Leonardo; Lugas, Massimo; Becca, Federico; Sorella, Sandro
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/14847
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