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 Erratum: 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):  
Graphene Nanoribbons ◽  
P Wave ◽  
Pairing Correlation ◽  
Wave Pairing ◽  
Zigzag Graphene Nanoribbons

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):  
Graphene Nanoribbons ◽  
P Wave ◽  
Pairing Correlation ◽  
Wave Pairing ◽  
Zigzag Graphene Nanoribbons

A survey on pure sampling in quantum Monte Carlo methods

2013 ◽  
Vol 91 (7) ◽  
pp. 505-510 ◽  
Author(s):  
Stuart M. Rothstein
Keyword(s):  
Monte Carlo ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Sampling Methods ◽  
Electrical Response ◽  
Distribution Functions ◽  
Monte Carlo Algorithm ◽  
Position Operator ◽  
Trial Solution ◽  
Mixed Distribution

The most commonly employed diffusion Monte Carlo algorithm and some of its variants afford a way to sample configuration space from a so-called “mixed distribution”, the product of an input trial solution to the Schrödinger equation for the ground state and its unknown exact solution. This mixed distribution is sufficient to compute the ground state energy and other properties represented by operators that commute with the Hamiltonian. These energy-related properties are exact, save for a small bias introduced by the input trial function’s incorrect exchange nodes, the so-called “fixed-node error”. However, properties represented by operators that commute with the position operator are also of interest. When calculated by sampling from the mixed distribution, these properties are much more strongly biased by the input trial function. Our objective is to review methods that allow sampling from the desired “pure” distribution, one that is unbiased except for the exchange node error. Thereby, one accurately calculates physical properties such as the dipole and other electrical moments, electrical response properties of molecules, and particle distribution functions for clusters. We survey the results of calculations that employ pure-sampling methods through what has been published in year 2012. Our review also touches on truly exact sampling methods.

scholarly journals Unconventional phase transitions in strongly anisotropic 2D (pseudo)spin systems

2018 ◽  
Vol 185 ◽  
pp. 08006
Author(s):  
Vitaly Konev ◽  
Evgeny Vasinovich ◽  
Vasily Ulitko ◽  
Yury Panov ◽  
Alexander Moskvin
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Phase Transitions ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Mean Field ◽  
Spin Systems ◽  
Field Approach ◽  
Generalized Mean

We have applied a generalized mean-field approach and quantum Monte-Carlo technique for the model 2D S = 1 (pseudo)spin system to find the ground state phase with its evolution under application of the (pseudo)magnetic field. The comparison of the two methods allows us to clearly demonstrate the role of quantum effects. Special attention is given to the role played by an effective single-ion anisotropy ("on-site correlation").

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