论文标题
拓扑绝缘体BI $ _2 $ te $ _3 $中的现场感应电荷对称性
Field induced charge symmetry in topological insulator Bi$_2$Te$_3$ revealed by nuclear magnetic resonance
论文作者
论文摘要
最近显示，通过$^{209} $ bi bi核四极杆互动的变化，核磁共振（NMR）测量了BI $ _2 $ SE $ _3 $的整体带反转，并且出人意料地发现了当地电场梯度的相应张量，令人惊讶的是，如果样品旋转了样品，则发现了当地电场梯度的相应张量。这表明了该拓扑绝缘子的大部分电荷载体的隐藏属性，在此探索了另一种材料Bi $ _2 $ te $ _3 $。发现两个电场梯度似乎存在于$^{209} $ bi，一个像往常一样，与晶格相处，而第二个则遵循外部场，如果将其相对于晶体轴旋转。这些电子自由度对应于$ j $ - 电子的有效旋转，它们的水平寿命被认为是造成新的四极松弛的原因，该释放应导致其他特殊特性，包括电子特定热量。
Nuclear magnetic resonance (NMR) was recently shown to measure the bulk band inversion of Bi$_2$Se$_3$ through changes in the $^{209}$Bi nuclear quadrupole interaction, and the corresponding tensor of the local electric field gradient was found to follow, surprisingly, the direction of the external magnetic field if the sample is rotated. This manifests a hidden property of the charge carriers in the bulk of this topological insulator, which is explored here with another material, Bi$_2$Te$_3$. It is found that two electric field gradients appear to be present at $^{209}$Bi, one rests with the lattice, as usual, while a second follows the external field if it is rotated with respect to the crystal axes. These electronic degrees of freedom correspond to an effective rotation of $j$-electrons, and their level life time is believed to be responsible for a new quadrupolar relaxation that should lead to other special properties including the electronic specific heat.
