Mechanisms of enhanced orbital dia- and paramagnetism: Application to the Rashba semiconductor BiTeI

从第一性原理计入 Van Vleck 顺磁性和 Langevin 抗磁性的所有贡献：应用于金刚石

Accounting all contributions for the Van Vleck paramagnetism and the Langevin diamagnetism from first principles: application to diamond

提出在单一磁规范下从头计算介电材料磁化率的方法，完整计入 Van Vleck 与 Langevin 贡献，并用 LAPW 计算金刚石，证实其磁化率各向同性且与实验吻合。

Possible quantum paramagnetism in compressed Sr$_2$IrO$_4$

The effect of compression on the magnetic ground state of Sr$_2$IrO$_4$ is studied with x-ray resonant techniques in the diamond anvil cell. The weak interlayer exchange coupling between square-planar 2D IrO$_2$ layers is readily modified upon compression, with a crossover between magnetic structures around 7 GPa mimicking the effect of an applied magnetic field at ambient pressure. Higher pressures drive an order-disorder magnetic phase transition with no magnetic order detected above 17-20 GPa. The persistence of strong exchange interactions between $\mathrm{J_{eff}}=1/2$ magnetic moments wi…

石墨抗磁性的弱非朗道型贡献

Weak non-Landau-type contributions to the diamagnetism of graphite

该研究从第一性原理计算了石墨中除朗道能级外的弱磁化率贡献，发现泡利顺磁性可忽略，而朗之万和范弗莱克机制的抗磁性贡献与面内实验值相当且轻微各向异性。

Spin-orbit coupling in octamers in a spinel sulfide CuIr$_2$S$_4$: Competition between spin-singlet and quadrupolar states, and its relevance to remnant paramagnetism

We theoretically investigate magnetic properties in the low-temperature phase with the formation of eight-site clusters, octamers, in the spinel compound CuIr$_2$S$_4$. The octamer state was considered to be a spin-singlet state induced by a Peieirls instability through the strong anisotropy of $d$ orbitals, the so-called orbital Peierls state. We reexamine this picture by taking into account the spin-orbit coupling which was ignored in the previous study. We derive a low-energy effective model between $j_{\rm eff}=1/2$ quasispins on Ir$^{4+}$ cations in an octamer from the multiorbital Hubbar…

The hidden magnetization in ferromagnetic material: Miamagnetism

This paper presents the hidden magnetization features of ferromagnetic materials: called miamagnetism. As we know, we have several forms of magnetization: the diamagnetism, the paramagnetism, the ferromagnetism etc. The main character of the diamagnetism is that its magnetic susceptibility is negative (from -1e-9 for gas and -1e-6 for liquid and solid to -1 for superconducting materials of type I) and it is not less than -1 unless for special materials like metamaterials at high frequencies. The miamagnetism has the character that the magnetic susceptibility can reach at low frequencies a nega…

Large Magnetic Susceptibility Anisotropy of Metallic Carbon Nanotubes

Through magnetic linear dichroism spectroscopy, the magnetic susceptibility anisotropy of metallic single-walled carbon nanotubes has been extracted and found to be 2-4 times greater than values for semiconducting single-walled carbon nanotubes. This large anisotropy is consistent with our calculations and can be understood in terms of large orbital paramagnetism of electrons in metallic nanotubes arising from the Aharonov-Bohm-phase-induced gap opening in a parallel field. We also compare our values with previous work for semiconducting nanotubes, which confirm a break from the prediction tha…