We analyze various possible superconducting pairing states and their relative stabilities in lightly doped graphene.It is shown that,when inter-sublattice electron-electron attractive interaction dominates and the Fer...We analyze various possible superconducting pairing states and their relative stabilities in lightly doped graphene.It is shown that,when inter-sublattice electron-electron attractive interaction dominates and the Fermi level is close to the Dirac points,the system will favor intra-valley spin-triplet p+ip pairing state.Based on the novel pairing state,we further propose a scheme for doing topological quantum computation in graphene by engineering local strain fields and external magnetic fields.展开更多
The total reciprocal space magnetic flux threading through a closed Fermi surface is a topological invariant for a three-dimensional metal.For a Weyl metal,the invariant is nonzero for each of its Fermi surfaces.We sh...The total reciprocal space magnetic flux threading through a closed Fermi surface is a topological invariant for a three-dimensional metal.For a Weyl metal,the invariant is nonzero for each of its Fermi surfaces.We show that such an invariant can be related to the magneto-valley-transport effect,in which an external magnetic field can induce a valley current.We further show that a strain field can drive an electric current,and that the effect is dictated by a second-class Chern invariant.These connections open the pathway to observe the hidden topological invariants in metallic systems.展开更多
We propose a general variational principle for mapping the interacting systems in continuous space to lattice models.Based on the principle,we derive a set of self-consistent nonlinear equations for the Wannier functi...We propose a general variational principle for mapping the interacting systems in continuous space to lattice models.Based on the principle,we derive a set of self-consistent nonlinear equations for the Wannier functions(or,equivalently for the Bloch functions).These equations show that the Wannier functions can be strongly influenced by the interaction and be significantly different from their non-interacting counterparts.The approach is demonstrated with interacting bosons in an optical lattice,and illustrated quantitatively by a simple model of interacting bosons in a double well potential.It is shown that the so-determined lattice model parameters can be significantly different from their non-interacting values.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2009CB929101.
文摘We analyze various possible superconducting pairing states and their relative stabilities in lightly doped graphene.It is shown that,when inter-sublattice electron-electron attractive interaction dominates and the Fermi level is close to the Dirac points,the system will favor intra-valley spin-triplet p+ip pairing state.Based on the novel pairing state,we further propose a scheme for doing topological quantum computation in graphene by engineering local strain fields and external magnetic fields.
基金Supported by the National Basic Research Program of China under Grant Nos 2009CB929101 and 2012CB921304.
文摘The total reciprocal space magnetic flux threading through a closed Fermi surface is a topological invariant for a three-dimensional metal.For a Weyl metal,the invariant is nonzero for each of its Fermi surfaces.We show that such an invariant can be related to the magneto-valley-transport effect,in which an external magnetic field can induce a valley current.We further show that a strain field can drive an electric current,and that the effect is dictated by a second-class Chern invariant.These connections open the pathway to observe the hidden topological invariants in metallic systems.
基金Supported by the National Natural Science Foundation of China under Grant No 10825417.
文摘We propose a general variational principle for mapping the interacting systems in continuous space to lattice models.Based on the principle,we derive a set of self-consistent nonlinear equations for the Wannier functions(or,equivalently for the Bloch functions).These equations show that the Wannier functions can be strongly influenced by the interaction and be significantly different from their non-interacting counterparts.The approach is demonstrated with interacting bosons in an optical lattice,and illustrated quantitatively by a simple model of interacting bosons in a double well potential.It is shown that the so-determined lattice model parameters can be significantly different from their non-interacting values.
