Measuring the magneto-conductivity induced from impurities may help determine the impurity distribution and reveal the structure of a Weyl semimetal sample.To verify this,we utilize the Gaussian random disorder to sim...Measuring the magneto-conductivity induced from impurities may help determine the impurity distribution and reveal the structure of a Weyl semimetal sample.To verify this,we utilize the Gaussian random disorder to simulate charged impurities in a two-node Weyl semimetal model and investigate the impact of charged impurities on magneto-conductivity in Weyl semimetals.We first compute the longitudinal magnetic conductivity and find that it is positive and increases proportionally with the parameter governing the Gaussian distribution of charged impurities,suggesting the presence of negative longitudinal magneto-resistivity.Then we consider both the intra-valley and inter-valley scattering processes to calculate the induced transverse magneto-conductivity in the model.Our findings indicate that both inter-valley and intravalley scattering processes play important roles in the transverse magneto-conductivity.The locations of Weyl nodes can also be determined by magneto-conductivity measurements.This is possible if the magnetic field strength and the density of charged impurities are known.Alternatively,the measurement of magnetic conductivity may reveal the distribution of charged impurities in a given sample once the locations of the Weyl nodes have been determined.These findings can aid in detecting the structure of a Weyl semimetal sample,enhancing comprehension of magnetotransport in Weyl semimetals and promoting the development of valley electronics.展开更多
Prompted by recent reports on √3×√3 graphene superlattices with intrinsic inter-valley interactions, we perform first-principles calculations to investigate the electronic properties of periodically nitrogen- ...Prompted by recent reports on √3×√3 graphene superlattices with intrinsic inter-valley interactions, we perform first-principles calculations to investigate the electronic properties of periodically nitrogen- doped graphene and carbon nanotube nanostruetures. In these structures, nitrogen atoms substitute one-sixth of the carbon atoms in the pristine hexagonal lattices with exact periodicity to form perfect √3×√3 superlattices of graphene and carbon nanotubes. Multiple nanostructures of √3×√3 graphene ribbons and carbon nanotubes are explored, and all configurations show nonmagnetic and metallic behaviors. The transport properties of √3×√3 graphene and carbon nanotube superlattices are calculated utilizing the non-equilibrium Green＇s function formalism combined with density functional theory. The translnission spectrum through the pristine and √3×√3 armchair carbon nanotube heterostructure shows quantized behavior under certain circumstances.展开更多
基金the National Natural Science Foundation of China(Grant No.61974162).
文摘Measuring the magneto-conductivity induced from impurities may help determine the impurity distribution and reveal the structure of a Weyl semimetal sample.To verify this,we utilize the Gaussian random disorder to simulate charged impurities in a two-node Weyl semimetal model and investigate the impact of charged impurities on magneto-conductivity in Weyl semimetals.We first compute the longitudinal magnetic conductivity and find that it is positive and increases proportionally with the parameter governing the Gaussian distribution of charged impurities,suggesting the presence of negative longitudinal magneto-resistivity.Then we consider both the intra-valley and inter-valley scattering processes to calculate the induced transverse magneto-conductivity in the model.Our findings indicate that both inter-valley and intravalley scattering processes play important roles in the transverse magneto-conductivity.The locations of Weyl nodes can also be determined by magneto-conductivity measurements.This is possible if the magnetic field strength and the density of charged impurities are known.Alternatively,the measurement of magnetic conductivity may reveal the distribution of charged impurities in a given sample once the locations of the Weyl nodes have been determined.These findings can aid in detecting the structure of a Weyl semimetal sample,enhancing comprehension of magnetotransport in Weyl semimetals and promoting the development of valley electronics.
基金This work was financially supported by the National Natural Science Foundation of China （Grants Nos. 11504240~ 11504241, and 11604213）, and the Natural Science Foundation of Shenzhen University （Grant No. 201550）. Z. Y. ac- knowledges the University Grant Council （Contract No. AoE/P- 04/08） of the Government of HKSAR.
文摘Prompted by recent reports on √3×√3 graphene superlattices with intrinsic inter-valley interactions, we perform first-principles calculations to investigate the electronic properties of periodically nitrogen- doped graphene and carbon nanotube nanostruetures. In these structures, nitrogen atoms substitute one-sixth of the carbon atoms in the pristine hexagonal lattices with exact periodicity to form perfect √3×√3 superlattices of graphene and carbon nanotubes. Multiple nanostructures of √3×√3 graphene ribbons and carbon nanotubes are explored, and all configurations show nonmagnetic and metallic behaviors. The transport properties of √3×√3 graphene and carbon nanotube superlattices are calculated utilizing the non-equilibrium Green＇s function formalism combined with density functional theory. The translnission spectrum through the pristine and √3×√3 armchair carbon nanotube heterostructure shows quantized behavior under certain circumstances.
