Quantum spin liquid emerging in two-dimensional correlated Dirac fermions

Article

关键词: VALENCE-BOND STATE;    MOTT INSULATOR;    HUBBARD-MODEL;    GROUND-STATE;    MONTE-CARLO;    TRIANGULAR LATTICE;    HONEYCOMB LATTICE;    OPTICAL LATTICE;    SUPERCONDUCTIVITY;    GRAPHENE;   

DOI  :  10.1038/nature08942

来源: SCIE

【 摘 要 】

At sufficiently low temperatures, condensed-matter systems tend to develop order. A notable exception to this behaviour is the case of quantum spin liquids, in which quantum fluctuations prevent a transition to an ordered state down to the lowest temperatures. There have now been tentative observations of such states in some two-dimensional organic compounds, yet quantum spin liquids remain elusive in microscopic two-dimensional models that are relevant to experiments. Here we show, by means of large-scale quantum Monte Carlo simulations of correlated fermions on a honeycomb lattice (a structure realized in, for example, graphene), that a quantum spin liquid emerges between the state described by massless Dirac fermions and an antiferromagnetically ordered Mott insulator. This unexpected quantum-disordered state is found to be a short-range resonating valence-bond liquid, akin to the one proposed for high-temperature superconductors: the possibility of unconventional superconductivity through doping therefore arises in our system. We foresee the experimental realization of this model system using ultra-cold atoms, or group IV elements arranged in honeycomb lattices.

【 授权许可】

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