Coexistence of magnetism and superconductivity in at−Jbilayer

Abstract

We investigate coexistence of antiferromagnetic and superconducting correlations in bilayered materials using a two-dimensional t-J model with couplings across the layers using variational Monte Carlo calculations. It is found that the underdoped regime supports a coexisting phase, beyond which the (d-wave) superconducting state becomes stable. Further, the effects of interplanar coupling parameters on the magnetic and superconducting correlations as a function of hole doping are studied in details. The magnetic correlations are found to diminish with increasing interplanar hopping away from half filling, while the exchange across the layers strengthens interplanar antiferromagnetic correlations both at and away from half filling. The superconducting correlations show more interesting features where larger interplanar hopping considerably reduces planar correlations at optimal doping, while an opposite behaviour, i.e. stabilisation of the superconducting state is realised in the overdoped regime, with the interplanar exchange all the while playing a dormant role.

Ground states of bilayered and extended t-J-U models

“…There are quite a number of studies on the bilayered or multilayered t-J type models in the literature [63][64][65][66][67][68][69]71,73,74]. Most of them are performed at the vanishing SDO or infinite Hubbard repulsion limit [63][64][65][66][67][68][69]71,73,74].…”

“…Most of them are performed at the vanishing SDO or infinite Hubbard repulsion limit [63][64][65][66][67][68][69]71,73,74]. Some of them focus on the SC and do not consider the AFM [63,64,[67][68][69].…”

“…Moreover, when UD and overdoped (OD) films of the La-214 cuprates are piled up [26], there can be an enhancement of the superconducting transition temperature to above that in the bare films. These observations suggest that interlayer coupling [57][58][59][60][61][62] may play a role and the ground states in monolayered and multilayered cuprates are unlike [63][64][65][66][67][68][69][70][71][72][73][74][75].…”

Effect of interlayer processes on the superconducting state within t-J-U model: Full Gutzwiller wave-function solution and relation to experiment

“…In this respect, a possible choice of pairing symmetries are discussed in Refs. 15 and 16. The inter-alyer pairing leads to deviations from the pure d-wave character of the superconducting order parameter what may be important in the context of some of the ARPES experiments indicating that the gap symmetry is more complex than a simple d-wave [17][18][19] .…”