4 research outputs found
Tunable van Hove singularity without structural instability in Kagome metal CsTiBi
In Kagome metal CsVSb, multiple intertwined orders are accompanied by
both electronic and structural instabilities. These exotic orders have
attracted much recent attention, but their origins remain elusive. The newly
discovered CsTiBi is a Ti-based Kagome metal to parallel CsVSb.
Here, we report angle-resolved photoemission experiments and first-principles
calculations on pristine and Cs-doped CsTiBi samples. Our results
reveal that the van Hove singularity (vHS) in CsTiBi can be tuned in a
large energy range without structural instability, different from that in
CsVSb. As such, CsTiBi provides a complementary platform to
disentangle and investigate the electronic instability with a tunable vHS in
Kagome metals
Spy Must Be Spotted: A Multistimuli-Responsive Luminescent Material for Dynamic Multimodal Anticounterfeiting and Encryption
The
development of luminescent materials for anticounterfeiting and encryption
is of great importance. Herein, we develop a multistimuli-responsive
luminescent material, Na<sub>2</sub>CaGe<sub>2</sub>O<sub>6</sub>:Pb<sup>2+</sup>/Er<sup>3+</sup>, and use it to print luminescent images.
The photoluminescence and upconversion luminescence of these images
show different patterns and colors under different stimuli. The photostimulated
luminescence (PSL) of the printed images causes dynamic changes in
appearance and is accordingly applied for dynamic multimodal anticounterfeiting
on banknotes. The PSL of these luminescent images is also applied
in a virtual war scenario to demonstrate that the dynamic PSL-encrypted
information in the fabricated image is sufficiently safe even in extreme
cases and that spies will be detected. These results can inspire us
with more creative security designs based on this luminescent material
Two-dimensional phase diagram of the charge density wave in doped CsV3Sb5
Abstract Kagome superconductors AV3Sb5 (A = K, Rb and Cs) have attracted much recent attention due to the coexistence of multiple exotic orders. Among them, the charge density wave (CDW) order has been shown to host various unconventional behaviors. Here, we investigate the CDW order by a combination of both bulk and surface doping methods. While element substitutions in bulk doping change both carriers and the crystal lattice, the surface doping primarily tunes the carrier concentration. As such, our results reveal a two-dimensional phase diagram of the CDW in doped CsV3Sb5. In the lightly bulk doped regime, the existence of CDW order is reversible by tuning the carrier concentration. But excessive bulk doping permanently destroys the CDW, regardless of the carrier doping level. These results provide insights to the origin of the CDW from both electronic and structural degrees of freedom. They also open an avenue for manipulating the exotic CDW order in Kagome superconductors
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Tunable Van Hove Singularity without Structural Instability in Kagome Metal CsTi3Bi5
In kagome metal CsV_{3}Sb_{5}, multiple intertwined orders are accompanied by both electronic and structural instabilities. These exotic orders have attracted much recent attention, but their origins remain elusive. The newly discovered CsTi_{3}Bi_{5} is a Ti-based kagome metal to parallel CsV_{3}Sb_{5}. Here, we report angle-resolved photoemission experiments and first-principles calculations on pristine and Cs-doped CsTi_{3}Bi_{5} samples. Our results reveal that the van Hove singularity (vHS) in CsTi_{3}Bi_{5} can be tuned in a large energy range without structural instability, different from that in CsV_{3}Sb_{5}. As such, CsTi_{3}Bi_{5} provides a complementary platform to disentangle and investigate the electronic instability with a tunable vHS in kagome metals