Abstract Electron band structure calculations and analysis of critical points parameters in the electron density distribution in Bi2Te3, Bi2Se3, Bi2S3, α-Bi2O3, Sb2Te3, Sb2Se3 and Sb2S3 at ambient and high pressures were performed to determine interrelations between the crystal structure, unusual physical (including magnetic and superconducting) properties and peculiarities in the electron density distribution. The programming code WIEN2k was used for band structure calculations. The previously found correlation between the superconducting transition temperature Tc and the electron density Laplacian value in the bond critical point with the highest electron density was confirmed by the calculations made for crystal structures under high pressure. The revealed parameters of bond critical points indicate the significant role of charge density fluctuations in the compounds studied. The 121, 123Sb NQR spin echo envelopes assigned to the ν1 transition (Δm = 1/2–3/2) were measured for the two crystallographic positions of Sb atoms in the Sb2S3 structure. Unexpectedly deep oscillations of NQR spin echo envelopes were observed in very small (1–3 Oe) external magnetic fields, evidencing for the existence of local magnetic fields in Sb2S3 similar to those earlier observed in bismuth oxide compounds.

中文翻译：

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铋和锑硫属元素化物：电子密度分布的特性、不寻常的磁性和超导性

摘要 进行了常压和高压下 Bi2Te3、Bi2Se3、Bi2S3、α-Bi2O3、Sb2Te3、Sb2Se3 和 Sb2S3 中电子密度分布的电子能带结构计算和临界点参数分析，以确定晶体结构、异常物理（包括磁性和超导）特性和电子密度分布的特性。编程代码 WIEN2k 用于能带结构计算。先前发现的超导转变温度 Tc 与具有最高电子密度的键临界点中的电子密度拉普拉斯值之间的相关性通过高压下晶体结构的计算得到证实。键临界点的揭示参数表明电荷密度波动在所研究的化合物中的重要作用。对于 Sb2S3 结构中 Sb 原子的两个晶体位置，测量了分配给 ν1 跃迁（Δm = 1/2–3/2）的 121、123Sb NQR 自旋回波包络。在非常小的 (1-3 Oe) 外部磁场中观察到 NQR 自旋回波包络的意外深度振荡，证明 Sb2S3 中存在局部磁场，类似于早先在氧化铋化合物中观察到的那些。