Based on first-principles calculations and symmetry arguments,we reveal that the non-centrosymmetric ternary tetradymite BiSbTe_(3) possesses exotic dual topological features of Weyl semimetallic phases with Z_(2) ind...Based on first-principles calculations and symmetry arguments,we reveal that the non-centrosymmetric ternary tetradymite BiSbTe_(3) possesses exotic dual topological features of Weyl semimetallic phases with Z_(2) index(1:000).The results show that the helical Dirac-type surface states protected by the time-reversal symmetry are present in the vicinity of the Brillouin zone center,which is consistent with the experimental report.Furthermore,we show that four pairs of Weyl points reside exactly at the Fermi level,which are guaranteed to be located on high-symmetry planes due to mirror symmetries.The helical surface states and the projected Weyl nodes are well separated in the momentum space,facilitating their observations in experiments.This work not only uncovers a unique quantum phenomenon with dual topological features in the tetradymite family but also paves a fascinating avenue for exploring the coexistence of multi-topological states with wide applications.展开更多
It has been demonstrated that many promising thermoelectric materials,such as tetradymite compounds are also threedimensional topological insulators.In both cases,a fundamental question is the evaluation of carrier re...It has been demonstrated that many promising thermoelectric materials,such as tetradymite compounds are also threedimensional topological insulators.In both cases,a fundamental question is the evaluation of carrier relaxation time,which is usually a rough task due to the complicated scattering mechanisms.Previous works using the simple deformation potential theory or considering complete electron-phonon coupling are,however,restricted to small systems.By adopting a data-driven method named SISSO(Sure Independence Screening and Sparsifying Operator)with the training data obtained via deformation potential theory,we propose an efficient and physically interpretable descriptor to evaluate the relaxation time,using tetradymites as prototypical examples.Without any input from first-principles calculations,the descriptor contains only several elemental properties of the constituent atoms,and could be utilized to quickly and reliably predict the carrier relaxation time of a substantial number of tetradymites with arbitrary stoichiometry.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.11604032,11674040,and 51672270)the Fundamental Research Funds for the Central Universities(Grant No.106112016CDJZR308808).
文摘Based on first-principles calculations and symmetry arguments,we reveal that the non-centrosymmetric ternary tetradymite BiSbTe_(3) possesses exotic dual topological features of Weyl semimetallic phases with Z_(2) index(1:000).The results show that the helical Dirac-type surface states protected by the time-reversal symmetry are present in the vicinity of the Brillouin zone center,which is consistent with the experimental report.Furthermore,we show that four pairs of Weyl points reside exactly at the Fermi level,which are guaranteed to be located on high-symmetry planes due to mirror symmetries.The helical surface states and the projected Weyl nodes are well separated in the momentum space,facilitating their observations in experiments.This work not only uncovers a unique quantum phenomenon with dual topological features in the tetradymite family but also paves a fascinating avenue for exploring the coexistence of multi-topological states with wide applications.
基金We thank financial support from the National Natural Science Foundation(Grant Nos.51772220 and 62074114).
文摘It has been demonstrated that many promising thermoelectric materials,such as tetradymite compounds are also threedimensional topological insulators.In both cases,a fundamental question is the evaluation of carrier relaxation time,which is usually a rough task due to the complicated scattering mechanisms.Previous works using the simple deformation potential theory or considering complete electron-phonon coupling are,however,restricted to small systems.By adopting a data-driven method named SISSO(Sure Independence Screening and Sparsifying Operator)with the training data obtained via deformation potential theory,we propose an efficient and physically interpretable descriptor to evaluate the relaxation time,using tetradymites as prototypical examples.Without any input from first-principles calculations,the descriptor contains only several elemental properties of the constituent atoms,and could be utilized to quickly and reliably predict the carrier relaxation time of a substantial number of tetradymites with arbitrary stoichiometry.
