Inducing and tuning Kondo screening in a narrow-electronic-band system

Abstract

Although the single-impurity Kondo physics has already been well understood, the understanding of the Kondo lattice where a dense array of local moments couples to the conduction electrons is still far from complete. The ability of creating and tuning the Kondo lattice in non-f-electron systems will be great helpful for further understanding the Kondo lattice behavior. Here we show that the Pb intercalation in the charge-density-wave-driven narrow-electronic-band system 1T-TaS2 induces a transition from the insulating gap to a sharp Kondo resonance in the scanning tunneling microscopy measurements. It results from the Kondo screening of the localized moments in the 13-site Star-of-David clusters of 1T-TaS2. As increasing the Pb concentration, the narrow electronic band derived from the localized electrons shifts away from the Fermi level and the Kondo resonance peak is gradually suppressed. Our results pave the way for creating and tuning many-body electronic states in layered narrow-electronic-band materials.

Is spontaneous vortex generation in superconducting 4Hb-TaS$_2$ from vison-vortex nucleation with $\mathbb{Z}_2$ topological order?

“…Although this vortex-memory effect was found to be absent in cuprates [15], this idea remains to be an ingenious attempt to detect the topological order beyond fractional quantum Hall liquids. In this Letter, we propose the superconducting van der Waals material 4Hb-TaS 2 [16,17] to be a physical platform for the Z 2 topological order, and interpret the recentlydiscovered magnetic memory effect and the spontaneous vortex generation [16] as the vison-vortex nucleation due to the Z 2 topological order. Our proposal for 4Hb-TaS 2 is a vortex lattice version of the Senthil-Fisher single-vortex proposal for cuprates, and bridges the puzzling experiments in 4Hb-TaS 2 with the forefront of topological orders and their detection.…”

“…The scanning tunneling microscopy on the isostructural monolayer 1T-TaSe 2 identified some evidences of the spinon Fermi surface in the cluster Mott insulating regime [29]. In contrast to the correlated insulating behavior in 1T-TaS 2 , the 1H-TaS 2 layer develops the 3 × 3 CDW and is a good metal at low temperatures [17]. The bulk form of 1H-TaS 2 , 2H-TaS 2 , superconducts at 0.7K.…”

“…Due to various tunability and controllability of their physical properties, the TaS 2 -based van der Waals materials [18] have attracted a great interest. Among these TaS 2 -based systems, the superconducting 4Hb-TaS 2 recently received some experimental attention [16,17]. Differing from other TaS 2based materials, the 4Hb-TaS 2 consists of an alternating stacking of 1T-TaS 2 and 1H-TaS 2 layers.…”

“…Once 1T-TaS 2 and 1H-TaS 2 layers are stacked together to form the bulk 4Hb-TaS 2 structure, the superconducting transition temperature T c is greatly enhanced, reaching 2.7K. This anomalous enhancement might arise from the charge transfer between the 1T and the 1H layers [16,17]. On the other hand, the insulating 1T-TaS 2 itself under the substitution of S with Se can superconduct with a maximal T c about 3.5K [30,31].…”

Moiré-driven multiferroic order in twisted CrCl$_3$, CrBr$_3$ and CrI$_3$ bilayers

“…Beyond isolating individual multiferroic monolayers, a potential alternative strategy to realize multiferroic order in van der Waals materials relies on artificially engineering it from originally non-multiferroic monolayers [12]. The electric control of magnetism provided by van der Waals multiferroics would open radically new ways of controlling artificial van der Waals matter, including Chern insulators [13][14][15][16], unconventional and topological superconductors [17][18][19][20][21][22] and correlated quantum magnets [23][24][25].…”