Three-dimensional type-ⅡWeyl fermions possess overtilted cone-like low-energy band dispersion.Unlike the closed ellipsoidal Fermi surface for type-ⅠWeyl fermions,the Fermi surface is an open hyperboloid for type-ⅡW...Three-dimensional type-ⅡWeyl fermions possess overtilted cone-like low-energy band dispersion.Unlike the closed ellipsoidal Fermi surface for type-ⅠWeyl fermions,the Fermi surface is an open hyperboloid for type-ⅡWeyl fermions.We evaluate the spin and density susceptibility of type-ⅡWeyl fermions with repulsive S-wave interaction by means of Green’s functions.We obtain the particle–hole continuum along the tilted momentum direction and perpendicular to the tilted momentum direction respectively.We find the zero sound mode in some repulsive interaction strengths by numerically solving the pole equations of the susceptibility within the random-phase approximation.展开更多
We calculate the spin and density susceptibility ofWeyl fermions with repulsive S-wave interaction in ultracold gases.Weyl fermions have a linear dispersion,which is qualitatively different from the parabolic dispersi...We calculate the spin and density susceptibility ofWeyl fermions with repulsive S-wave interaction in ultracold gases.Weyl fermions have a linear dispersion,which is qualitatively different from the parabolic dispersion of conventional materials.We find that there are different collective modes for the different strengths of repulsive interaction by solving the poles equations of the susceptibility in the random-phase approximation.In the long-wavelength limit,the sound velocity and the energy gaps vary with the different strengths of the interaction in the zero sound mode and the gapped modes,respectively.The particle-hole continuum is obtained as well,where the imaginary part of the susceptibility is nonzero.展开更多
基金supported by the National Key R&D Program of China(Grant No.2016YFA0301500)the National Natural Science Foundation of China(Grants No.61835013)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB01020300 and XDB21030300)。
文摘Three-dimensional type-ⅡWeyl fermions possess overtilted cone-like low-energy band dispersion.Unlike the closed ellipsoidal Fermi surface for type-ⅠWeyl fermions,the Fermi surface is an open hyperboloid for type-ⅡWeyl fermions.We evaluate the spin and density susceptibility of type-ⅡWeyl fermions with repulsive S-wave interaction by means of Green’s functions.We obtain the particle–hole continuum along the tilted momentum direction and perpendicular to the tilted momentum direction respectively.We find the zero sound mode in some repulsive interaction strengths by numerically solving the pole equations of the susceptibility within the random-phase approximation.
基金Project supported by the National Natural Science Foundation of China(Grant No.2016YFA0301500).
文摘We calculate the spin and density susceptibility ofWeyl fermions with repulsive S-wave interaction in ultracold gases.Weyl fermions have a linear dispersion,which is qualitatively different from the parabolic dispersion of conventional materials.We find that there are different collective modes for the different strengths of repulsive interaction by solving the poles equations of the susceptibility in the random-phase approximation.In the long-wavelength limit,the sound velocity and the energy gaps vary with the different strengths of the interaction in the zero sound mode and the gapped modes,respectively.The particle-hole continuum is obtained as well,where the imaginary part of the susceptibility is nonzero.
