Understanding the interplay between screening,electronic correlations,and collective excitations is essential for the design of two-dimensional quantum materials.Here,we present a comprehensive first-principles study ...Understanding the interplay between screening,electronic correlations,and collective excitations is essential for the design of two-dimensional quantum materials.Here,we present a comprehensive first-principles study of more than 60 MA_(2)Z_(4)monolayers,encompassing semiconducting,metallic,cold-metallic,magnetic,and topological phases.Using the constrained random phase approximation(cRPA),wecompute material-specific effectiveCoulomb interaction parametersU,U0,and J,including their spatial dependence across distinct correlated subspaces defined by local coordination and crystal symmetry.In semiconducting compounds,long-range nonlocal interactions persist,revealing unconventional screening and suggesting strong excitonic effects beyond simple dielectricmodels.In cold-metallic systems,sizable long-range Coulomb interactions remain despite the presence of free carriers,highlighting their atypical metallic screening.Among 33-valence-electron compounds,we find U^(eff)>W in theβ2 phase,indicating proximity to charge-density-wave or Mott instabilities.Several V-and Nb-based systems exhibit intermediate-to-strong correlation strength,with U/W>1 in multiple cases.Using cRPA-derived Stoner parameters,we identify magnetic instabilities in various V-,Nb-,Cr-,andMn-based compounds.Finally,selected cold-metallic systems display plasmon dispersions that deviate from the conventional√q behavior,revealing nearly non-dispersive low-energy modes.These results position MA_(2)Z_(4)monolayers as a versatile platform for investigating correlation-driven instabilities and emergent collective behavior in two dimensions.展开更多
基金supported by the Iran National Science Foundation(INSF)under Project No.4044100the Collaborative Research Center CRC/TRR 227 of the Deutsche Forschungsgemeinschaft(DFG),and the European Union(EFRE)via Grant No.ZS/2016/06/79307.
文摘Understanding the interplay between screening,electronic correlations,and collective excitations is essential for the design of two-dimensional quantum materials.Here,we present a comprehensive first-principles study of more than 60 MA_(2)Z_(4)monolayers,encompassing semiconducting,metallic,cold-metallic,magnetic,and topological phases.Using the constrained random phase approximation(cRPA),wecompute material-specific effectiveCoulomb interaction parametersU,U0,and J,including their spatial dependence across distinct correlated subspaces defined by local coordination and crystal symmetry.In semiconducting compounds,long-range nonlocal interactions persist,revealing unconventional screening and suggesting strong excitonic effects beyond simple dielectricmodels.In cold-metallic systems,sizable long-range Coulomb interactions remain despite the presence of free carriers,highlighting their atypical metallic screening.Among 33-valence-electron compounds,we find U^(eff)>W in theβ2 phase,indicating proximity to charge-density-wave or Mott instabilities.Several V-and Nb-based systems exhibit intermediate-to-strong correlation strength,with U/W>1 in multiple cases.Using cRPA-derived Stoner parameters,we identify magnetic instabilities in various V-,Nb-,Cr-,andMn-based compounds.Finally,selected cold-metallic systems display plasmon dispersions that deviate from the conventional√q behavior,revealing nearly non-dispersive low-energy modes.These results position MA_(2)Z_(4)monolayers as a versatile platform for investigating correlation-driven instabilities and emergent collective behavior in two dimensions.
