scholarly journals Superconductivity in the doped Hubbard model and its interplay with next-nearest hopping t′

Science ◽  
2019 ◽  
Vol 365 (6460) ◽  
pp. 1424-1428 ◽  
Author(s):  
Hong-Chen Jiang ◽  
Thomas P. Devereaux

The Hubbard model is widely believed to contain the essential ingredients of high-temperature superconductivity. However, proving definitively that the model supports superconductivity is challenging. Here, we report a large-scale density matrix renormalization group study of the lightly doped Hubbard model on four-leg cylinders at hole doping concentration δ = 12.5%. We reveal a delicate interplay between superconductivity and charge density wave and spin density wave orders tunable via next-nearest neighbor hopping t′. For finite t′, the ground state is consistent with a Luther-Emery liquid with power-law superconducting and charge density wave correlations associated with half-filled charge stripes. In contrast, for t′ = 0, superconducting correlations fall off exponentially, whereas charge density and spin density modulations are dominant. Our results indicate that a route to robust long-range superconductivity involves destabilizing insulating charge stripes in the doped Hubbard model.

2014 ◽  
Vol 28 (06) ◽  
pp. 1450042 ◽  
Author(s):  
Hanqin Ding ◽  
Jun Zhang

In this paper, we study analytically a half-filled generalized Hubbard chain with a quite general nearest-neighbor interaction, parametrized by diagonal repulsion V, off-diagonal pair-hopping and correlated-hopping repulsions W, X and antiferromagnetic spin exchange J for small values of the interactions. The ground state phase diagram is obtained in the weak-coupling regime. Besides the charge-density-wave (CDW) and spin-density-wave (SDW) phases for large 2V/U and U/2V, respectively, we identify a bond-spin-density-wave (BSDW) for J/W < 2, 3J/2 - 2W < 2V - U < 2W - J/2 and bond-charge-density-wave (BCDW) phase for J/W > 2, 2W - J/2 < 2V - U < 3J/2 - 2W. The modulating effect of W and J is responsible for the emergence of BSDW and BCDW phases, which, however, are decreased weakly by the Umklapp scattering of parallel-spin electrons.


2014 ◽  
Vol 83 (4) ◽  
pp. 044715 ◽  
Author(s):  
Shoichi Tomiyoshi ◽  
Hiroyuki Ohsumi ◽  
Hisao Kobayashi ◽  
Akiji Yamamoto

1993 ◽  
Vol 07 (01n03) ◽  
pp. 620-623 ◽  
Author(s):  
R.S. FISHMAN ◽  
S.H. LIU

It is well-known that impurities profoundly alter the magnetic properties of chromium. While vanadium impurities suppress the Néel temperature TN, manganese impurities enhance TN substantially. As evidenced by neutron scattering experiments, doping with as little as 0.2% vanadium changes the transition from weakly first order to second order. Young and Sokoloff explained that the first-order transition in pure chromium is caused by a charge-density wave which is the second harmonic of the spin-density wave. By examining the subtle balance between the spin-density and charge-density wave terms in the mean-field free energy, we find that the first-order transition is destroyed when the vanadium concentration exceeds about 0.15%, in agreement with experiments.


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