AI 中文总结
该研究针对手性一维有机-无机混合铅卤化物钙钛矿提出单轨道紧束缚模型，由原胞位点的单个有效轨道构建，含多种自由度，能再现能带色散与自旋分裂，还分析了偶然简并性，为理解其电子结构及相关响应提供起点。
AI 中文摘要
我们提出了一种用于手性一维有机-无机混合铅卤化物钙钛矿（R/S-PEA）PbI₃低能电子态的单轨道紧束缚模型。该模型由原胞中四个对称相关位点上的单个有效轨道构建而成，包含层、面内亚晶格和自旋自由度。使用单独的导带和价带参数集，有效哈密顿量再现了密度泛函理论计算得到的整体能带色散，并定量捕捉了带边附近的自旋分裂。它还捕捉了布洛赫态的主要自旋极化模式。我们进一步使用螺旋本征值和反酉算符分析了有效哈密顿量的偶然简并性。该模型为理解手性铅卤化物钙钛矿的带边电子结构以及分析此类材料的光学、自旋和输运响应提供了一个对称透明的起点。
英文摘要
We present a single-orbital tight-binding model for the low-energy electronic states of the chiral one-dimensional hybrid organic-inorganic lead halide perovskite $\mathrm{(}R/S\mathrm{-PEA)PbI}_3$. The model is constructed from a single effective orbital on each of the four symmetry-related sites in the primitive unit cell and incorporates layer, in-plane sublattice, and spin degrees of freedom. Using separate parameter sets for the conduction and valence bands, the effective Hamiltonian reproduces the overall band dispersions obtained from density-functional-theory calculations and quantitatively captures the spin splittings near the band edges. It also captures the leading spin-polarization patterns of the Bloch states, showing that the band-edge spin splitting and spin polarization are encoded in a small number of symmetry-adapted spin-dependent hopping terms. We further analyze the accidental degeneracies of the effective Hamiltonian using screw eigenvalues and antiunitary operators. This analysis separates accidental degeneracies originating from the restricted term content of the effective Hamiltonian from degeneracies enforced by nonsymmorphic screw symmetries and time-reversal symmetry. The present model provides a symmetry-transparent starting point for understanding the band-edge electronic structure of chiral lead halide perovskites and for analyzing optical, spin, and transport responses in this class of materials.
Comments13 pages, 5 figures
