Fragment-orbital-dependent spin fluctuations in the single-component molecular conductor [Ni(dmdt)2]
Fragment-orbital-dependent spin fluctuations in the single-component molecular conductor [Ni(dmdt)2]
复制标题
单组分分子导体中片段轨道相关的自旋涨落 [Ni(dmdt)2]
DOI：
10.1103/physrevb.105.205145
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发表时间：
2022
影响因子：
3.7
通讯作者：
Kobayashi Akito
中科院分区：
文献类型：
--
作者：
Kawamura Taiki;Kobayashi Akito
受最近的核磁共振实验的启发，我们在描述该化合物中的Dirac节线电子系统的多轨道Hubbard模型中使用无规相位近似计算了单组分分子导体的自旋磁化率、Knight位移和自旋-晶格弛豫速率。这个Hubbard模型由三个碎片轨道和使用从头算任意体微扰理论计算得到的原位排斥相互作用组成。我们发现了与碎片轨道相关的自旋涨落与动量和一个无公度的波数值，在该值处自旋磁化率的对角元素是最大的。在低温和高温下，以费米口袋能量尺度为边界，响应分别占主导地位。结果表明，随着温度的降低，Knight位移逐渐减小，但在低温时，由于自旋涨落的影响，Knight位移开始增大，而Knight位移则保持单调减小的趋势。这些性质是由于该Dirac节线系统的特征波函数所引起的分子内反铁磁涨落所引起的，该系统可用带模型描述。结果表明，碎片轨道在磁性中起着重要作用。
Motivated by recent nuclear magnetic resonance experiments, we calculated the spin susceptibility, Knight shift, and spin-lattice relaxation rate () of the single-component molecular conductorusing the random phase approximation in a multi-orbital Hubbard model describing the Dirac nodal line electronic system in this compound. This Hubbard model is composed of three fragment orbitals and on-site repulsive interactions obtained usingab initiomany-body perturbation theory calculations. We found fragment-orbital-dependent spin fluctuations with the momentumand an incommensurate value of the wave numberat which a diagonal element of the spin susceptibility is maximum. Theandresponses become dominant at low and high temperatures, respectively, with the Fermi-pocket energy scale as the boundary. We show thatdecreases with decreasing temperature, but starts to increase at low temperature owing to thespin fluctuations, while the Knight shift keeps monotonically decreasing. These properties are due to the intramolecular antiferromagnetic fluctuations caused by the characteristic wave functions of this Dirac nodal line system, which is described by an-band () model. We show that the fragment orbitals play important roles in the magnetic properties of.