论文标题
$ ab $ $ $ $ unitio $低能量有效的高温超导超导杯bi $ _2 $ _2 $ sr $ _2 $ _2 $ cuo $ _6 $，bi $ _2 $ _2 $ _2 $ _2 $ _2 $ _2 $ cacu $ _2 $ _2 $ _2 $ _ $ _ $ _2 $ _2 $ _2 $ _2 $ $ $ $ $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _4 $ _444444444444444444岁。
$Ab$ $initio$ low-energy effective Hamiltonians for high-temperature superconducting cuprates Bi$_2$Sr$_2$CuO$_6$, Bi$_2$Sr$_2$CaCu$_2$O$_8$, HgBa$_2$CuO$_4$ and CaCuO$_2$
论文作者
论文摘要
我们得出$ ab $ $ $ $ $ $低能量有效的哈密顿人（LEH），用于高温超导（SC）铜氧化物bi $ _2 $ _2 $ _2 $ _2 $ cuo $ _6 $（bi2201，$ n _ {\ ell _ {\ ell} Bi $ _2 $ sr $ _2 $ cacu $ _2 $ o $ o $ _8 $（bi2212，$ n _ {\ ell} = 2 $，$ t_c^{\ rm exp} \ sim 84 $ k） $ t_c^{\ rm exp} \ sim 90 $ k）和cacuo $ _2 $（ca11，$ n _ {\ ell} = \ infty $，$ t_c^{\ rm exp} \ sim 110 $ k），具有不同的实验性最佳SC TREAXITION SC TREXITION SC TREXITION SC TREVITINID $ T_C^$ eell $ eeld $ eell $} $} $ rmm -frim -el}层压cuo $ _2 $飞机在两个相邻的块层之间。我们应用了相关电子系统（MACE）的多尺度$ ab $ $ $ $ $ $ $ $ $ $ $ $的方法，并专注于由一个抗Bonding（AB）Cu $ 3D_ {X^2-y^2} $/O $2P_σ$ Orbital组成的LEH。我们讨论此LEH的突出特征：（1）在现场有效库仑排斥（ECR）$ U $和最近邻居跳跃$ t_1 $的振幅之间的比率$ u/| t_1 | $，随着$ t^{\ rm exp} _c} _c} _c $和$ n _ _ {\ ell} $ corration $ t_1 $的振幅增加$ p_ {dd} $带有$ u/| t_1 | $。增加$ u/| t_1 | $增加的一个可能原因是当$ n _ {\ ell} $增加时，cu原子替换了cu原子的顶端o原子。此外，我们表明，Cu和顶端O原子之间的距离增加会降低LEH外的电子的有效筛选（ES），并增加了$ u/| t_1 | $。 （2）对于HG1201和CA11，我们表明$ u/| t_1 | $在每AB轨道$δ$增加时会减小，当$δ$超过实验中最佳值时，这可能部分解释了SC的消失。 （3）对于$ n _ {\ ell} \ geq 2 $，非现场cuo $ _2 $ plane ecr可与现场非现场intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra Intra。我们讨论了cuo $ _2 $ ecr的贡献对$ p_ {dd} $和SC状态的稳定性。
We derive $ab$ $initio$ low-energy effective Hamiltonians (LEH) for high-temperature superconducting (SC) copper oxides Bi$_2$Sr$_2$CuO$_6$ (Bi2201, $N_{\ell}=1$, $T_c^{\rm exp} \sim 10$ K), Bi$_2$Sr$_2$CaCu$_2$O$_8$ (Bi2212, $N_{\ell}=2$, $T_c^{\rm exp} \sim 84$ K), HgBa$_2$CuO$_4$ (Hg1201, $N_{\ell}=1$, $T_c^{\rm exp} \sim 90$ K) and CaCuO$_2$ (Ca11, $N_{\ell}=\infty$, $T_c^{\rm exp} \sim 110$ K), with different experimental optimal SC transition temperature $T_c^{\rm exp}$ and number $N_{\ell}$ of laminated CuO$_2$ planes between the two neighboring block layers. We apply the latest methodology of the multiscale $ab$ $initio$ scheme for correlated electron systems (MACE), and focus on the LEH consisting of one antibonding (AB) Cu$3d_{x^2-y^2}$/O$2p_σ$ orbital centered on each Cu atom. We discuss prominent features of this LEH: (1) The ratio $U/|t_1|$ between the onsite effective Coulomb repulsion (ECR) $U$ and amplitude of nearest neighbour hopping $t_1$ increases with $T^{\rm exp}_c$ and $N_{\ell}$, consistently with the expected increase in $d$-wave SC correlation function $P_{dd}$ with $U/|t_1|$. One possible cause of the increase of $U/|t_1|$ is the replacement of apical O atoms by Cu atoms from neighbouring CuO$_2$ planes when $N_{\ell}$ increases. Furthermore, we show that the increase in distance between Cu and apical O atoms decreases the effective screening (ES) by electrons outside of the LEH and increases $U/|t_1|$. (2) For Hg1201 and Ca11, we show that $U/|t_1|$ decreases when hole doping per AB orbital $δ$ increases, which may partly account for the disappearance of SC when $δ$ exceeds the optimal value in experiment. (3) For $N_{\ell} \geq 2$, off-site inter-CuO$_2$ plane ECR is comparable to off-site intra-CuO$_2$ plane ECR. We discuss contributions of inter-CuO$_2$ plane ECR to both $P_{dd}$ and the stability of the SC state.
