Multipole polaron in the devil's staircase of CeSb
Multipole polaron in the devil's staircase of CeSb
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DOI：
10.1038/s41563-021-01188-9
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发表时间：
2022-02-10
期刊：
影响因子：
41.2
通讯作者：
Kondo, Takeshi
中科院分区：
文献类型：
--
作者：
Arai, Y.;Kuroda, Kenta;Kondo, Takeshi
稀土金属间化合物表现出丰富的局域f轨道和传导电子相互作用的现象。然而，由于晶体电场分裂的能量尺度只有几个毫伏，伴随集体晶体电场激发的移动的电子的性质还没有被揭示。在这里，我们研究低能量的电子结构CeSb通过异常的磁结构转变低于尼尔温度，类似于17 K，被称为“魔鬼的楼梯”，使用激光角分辨光电子能谱，拉曼和中子散射光谱。我们报告了另一种类型的电子玻色子之间的耦合移动的电子和四极晶体电场激发的4f轨道，显着重整化的Sb 5p带，产生一个扭结在一个非常低的能量（类似于7毫电子伏）。这种耦合强度是强大的，并表现出异常的阶梯状增强在魔鬼的楼梯过渡，揭示了一种新型的准粒子，命名为“多极极化子”，包括一个移动的电子穿着云的四极晶体电场极化。
Rare-earth intermetallic compounds exhibit rich phenomena induced by the interplay between localized f orbitals and conduction electrons. However, since the energy scale of the crystal-electric-field splitting is only a few millielectronvolts, the nature of the mobile electrons accompanied by collective crystal-electric-field excitations has not been unveiled. Here, we examine the low-energy electronic structures of CeSb through the anomalous magnetostructural transitions below the Neel temperature, similar to 17K, termed the 'devil's staircase', using laser angle-resolved photoemission, Raman and neutron scattering spectroscopies. We report another type of electron-boson coupling between mobile electrons and quadrupole crystal-electric-field excitations of the 4f orbitals, which renormalizes the Sb 5p band prominently, yielding a kink at a very low energy (similar to 7 meV). This coupling strength is strong and exhibits anomalous step-like enhancement during the devil's staircase transition, unveiling a new type of quasiparticle, named the 'multipole polaron', comprising a mobile electron dressed with a cloud of the quadrupole crystal-electric-field polarization.