289 research outputs found
Character of frustration on magnetic correlation in doped Hubbard model
The magnetic correlation in the Hubbard model on a two-dimensional
anisotropic triangular lattice is studied by using the determinant quantum
Monte Carlo method. Around half filling, it is found that the increasing
frustration could change the wave vector of maximum spin correlation
along
()()()
(), indicating the frustration's remarkable
effect on the magnetism. In the studied filling region =1.0-1.3, the doping
behaves like some kinds of {\it{frustration}}, which destroys the
AFM correlation quickly and push the magnetic order to a wide range of the
order when the is large
enough. Our non-perturbative calculations reveal a rich magnetic phase diagram
over both the frustration and electron doping.Comment: 6 pages, 7 figure
Electronic band gaps and transport in aperiodic graphene superlattices of Thue-Morse sequence
We have studied the electronic properties in aperiodic graphene superlattices
of Thue-Morse sequence. Although the structure is aperiodic, an unusual Dirac
point (DP) does exist and its location is exactly at the position of the
zero-averaged wave number (zero-. Furthermore, the zero- gap
associated with the DP is robust against the lattice constants and the incident
angles, and multi-DPs can appear under the suitable conditions. A resultant
controllability of electron transport in Thue-Morse sequence is predicted,
which may facilitate the development of many graphene-based electronics.Comment: Accepted for publication in Applied Physics Letters; 4 pagese, 5
figure
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