In uranium-based heavy fermion systems, the $5f$ electrons display an intermediate character between partial localization and partial itinerancy, which makes the Kondo problem more complicated. Here we use scanning tunneling microscopy/spectroscopy to investigate the (001) surface of the Kondo lattice antiferromagnet ${\mathrm{USb}}_2$. Temperature-dependent $dI/dV$ spectra from 4.7 K up to 140 K reveal several peak structures around the Fermi level. Two pronounced peaks originate from the hybridization between the conduction and $5f$ electrons. We did not observe the mysteriously abrupt change of the electronic state at 45 K, which was previously reported by another scanning tunneling microscopy group and attributed to a novel first-order-like transition. Instead, we only observe continuous evolution of the $dI/dV$ spectra with temperature. Furthermore, in some scanning regions, we find significant Sb atoms missing from the top layer, which gives us the opportunity to investigate the electronic structure of the U-terminated surface. For the U-terminated surface, an additional sharp peak emerges, which is closely related to the magnetic order.

中文翻译：

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反铁磁近藤晶格USb2中5f电子的局部到巡回跃迁的交叉行为

在铀基重费米子系统中， $5F$电子显示出部分定位和部分巡回之间的中间特征，这使得 Kondo 问题更加复杂。在这里，我们使用扫描隧道显微镜/光谱来研究 Kondo 晶格反铁磁体的 (001) 表面${\mathrm{USB}}_2$. 温度相关$d\mathrm{一世}/d伏$从 4.7 K 到 140 K 的光谱揭示了费米能级周围的几个峰结构。两个明显的峰值源于传导和$5F$电子。我们没有观察到 45 K 时电子状态的神秘突然变化，这是另一个扫描隧道显微镜组先前报道的，并归因于一种新的类一阶跃迁。相反，我们只观察到$d\mathrm{一世}/d伏$光谱与温度。此外，在某些扫描区域，我们发现顶层缺少大量的 Sb 原子，这使我们有机会研究 U 端表面的电子结构。对于 U 端表面，会出现一个额外的尖峰，这与磁序密切相关。