scholarly journals Interplay between the edge-state magnetism and long-range Coulomb interaction in zigzag graphene nanoribbons: Quantum Monte Carlo study

2017 ◽  
Vol 96 (11) ◽  
Author(s):  
Marcin Raczkowski ◽  
Fakher F. Assaad
Keyword(s):  
Monte Carlo ◽  
Long Range ◽  
Coulomb Interaction ◽  
Quantum Monte Carlo ◽  
Graphene Nanoribbons ◽  
Monte Carlo Study ◽  
Edge State ◽  
Zigzag Graphene Nanoribbons

QUANTUM MONTE CARLO STUDY OF MAGNETIC CORRELATION IN GRAPHENE NANORIBBONS AND QUANTUM DOTS

2013 ◽  
Vol 27 (21) ◽  
pp. 1330016
Author(s):  
PAN GAO ◽  
SUHANG LIU ◽  
LIN TIAN ◽  
TIANXING MA
Keyword(s):  
Monte Carlo ◽  
Quantum Monte Carlo ◽  
Nearest Neighbor ◽  
Graphene Nanoribbons ◽  
Monte Carlo Study ◽  
Electron Interaction ◽  
Magnetic Correlation ◽  
Antiferromagnetic Correlation ◽  
Armchair Graphene Nanoribbons ◽  
Armchair Graphene

To realize the application of spintronics, possible magnetism in graphene-based material is an important issue to be addressed. At the tight banding level of armchair graphene nanoribbons, there are two flat bands in the band structure, two Van Hove singularities in the density of states, and the introducing of the next-nearest-neighbor hopping term cause high asymmetry in them, which plays a key role in the behavior of magnetic correlation. We further our studies within determinant quantum Monte Carlo simulation to treat the electron–electron interaction. It is found that the armchair graphene nanoribbons show carrier mediated magnetic correlation. In the armchair graphene nanoribbons, the antiferromagnetic correlation dominates around half filling, while the ferromagnetic correlation dominates as electron filling is lower than 0.8. Moreover, the ferromagnetic correlation is strengthened markedly as the next-nearest-neighbor hopping energy increases. The resultant manipulation of ferromagnetism in graphene-based material may facilitate the development of spintronics.

scholarly journals Triplet p-wave pairing correlation in low-doped zigzag graphene nanoribbons

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Tianxing Ma ◽  
Fan Yang ◽  
Zhongbing Huang ◽  
Hai-Qing Lin
Keyword(s):  
Monte Carlo ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Graphene Nanoribbons ◽  
Random Phase ◽  
P Wave ◽  
Pairing Correlation ◽  
Wave Pairing ◽  
Spin Triplet ◽  
Zigzag Graphene Nanoribbons

Abstract We reveal an edge spin triplet p–wave superconducting pairing correlation in slightly doped zigzag graphene nanoribbons. By employing a method that combines random-phase approximation, the finite-temperature determinant quantum Monte Carlo approach, and the ground-state constrained-path quantum Monte Carlo method, it is shown that such a spin-triplet pairing is mediated by the ferromagnetic fluctuations caused by the flat band at the edge. The spin susceptibility and effective pairing interactions at the edge strongly increase as the on-site Coulomb interaction increases, indicating the importance of electron-electron correlations. It is also found that the doping-dependent ground-state p-wave pairing correlation bears some similarity to the famous superconducting dome in the phase diagram of a high-temperature superconductor, while the spin correlation at the edge is weakened as the system is doped away from half filling.

scholarly journals Quantum spin models with long-range interactions and tunnelings: a quantum Monte Carlo study

2012 ◽  
Vol 14 (11) ◽  
pp. 113006 ◽  
Author(s):  
Michał Maik ◽  
Philipp Hauke ◽  
Omjyoti Dutta ◽  
Jakub Zakrzewski ◽  
Maciej Lewenstein
Keyword(s):  
Monte Carlo ◽  
Long Range ◽  
Quantum Monte Carlo ◽  
Monte Carlo Study ◽  
Quantum Spin ◽  
Spin Models ◽  
Long Range Interactions ◽  
Quantum Spin Models
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