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1. Measurement of the dynamic charge susceptibility near the charge density wave transition in ErTe3

   Chaudhuri, Dipanjan; Jiang, Qianni; Guo, Xuefei; Chen, Ji; Kengle, Caitlin S; Hoveyda-Marashi, Farzaneh; Bernal-Choban, Camille; de_Vries, Niels; Chiang, Tai C; Fradkin, Eduardo; et al (December 2024, 2411.14746)

   A charge density wave (CDW) is a phase of matter characterized by a periodic modulation of the valence electron density accompanied by a distortion of the lattice structure. The microscopic details of CDW formation are closely tied to the dynamic charge susceptibility, χ(q, ω), which describes the behavior of electronic collective modes. Despite decades of extensive study, the behavior of χ(q, ω) in the vicinity of a CDWtransition has never been measured with high energy resolution (∼meV). Here, we investigate the canonical CDW transition in ErTe3 using momentum-resolved electron energy loss spectroscopy (M-EELS), a technique uniquely sensitive to valence band charge excitations. Unlike phonons in these materials, which undergo conventional softening due to the Kohn anomaly at the CDW wavevector, the electronic excitations display purely relaxational dynamics that are well described by a diffusive model. The diffusivity peaks around 250 K, just below the critical temperature. Additionally, we report, for the first time, a divergence in the real part of χ(q, ω) in the static limit (ω → 0), a phenomenon predicted to characterize CDWs since the 1970s. These results highlight the importance of energy- and momentum-resolved measurements of electronic susceptibility and demonstrate the power of M-EELS as a versatile probe of charge dynamics in materials. 

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2. Dipole Charge Detection: Toward the Readout of Bistable Charge States in Molecular QCA

   https://doi.org/10.1109/LSENS.2023.3322265  

   Rahaman, Mohammad Istiaque; Szakmany, Gergo P; Orlov, Alexei O; Snider, Gregory L (January 2024, IEEE Sensors Letters)
3. Effects of charge fluctuation and charge regulation on the phase transitions in stoichiometric VO2

   https://doi.org/10.1038/s41598-020-73447-9  

   Joshi, Siddharth; Smieszek, Nicholas; Chakrapani, Vidhya (October 2020, Scientific Reports)

   Abstract Detailed electrical and photoemission studies were carried out to probe the chemical nature of the insulating ground state of VO₂, whose properties have been an issue for accurate prediction by common theoretical probes. The effects of a systematic modulation of oxygen over-stoichiometry of VO₂from 1.86 to 2.44 on the band structure and insulator–metal transitions are presented for the first time. Results offer a different perspective on the temperature- and doping-induced IMT process. They suggest that charge fluctuation in the metallic phase of intrinsic VO₂results in the formation of e⁻and h⁺pairs that lead to delocalized polaronic V³⁺and V⁵⁺cation states. The metal-to-insulator transition is linked to the cooperative effects of changes in the V–O bond length, localization of V³⁺electrons at V⁵⁺sites, which results in the formation of V⁴⁺–V⁴⁺dimers, and removal of$$\pi^{*}$$ ${\pi }^{\ast }$screening electrons. It is shown that the nature of phase transitions is linked to the lattice V³⁺/V⁵⁺concentrations of stoichiometric VO₂and that electronic transitions are regulated by the interplay between charge fluctuation, charge redistribution, and structural transition. 

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4. Charge Transfer within Metal-Organic Frameworks: The Role of Polar Node in the Electrocatalysis and Charge Storage

   https://doi.org/10.1149/08513.0559ecst  

   Yu, Jierui; Wyk, Andrea Van; Smith, Tanner; Deria, Pravas (June 2018, ECS Transactions)
5. Spin-Charge-Lattice Coupling across the Charge Density Wave Transition in a Kagome Lattice Antiferromagnet

   https://doi.org/10.1103/PhysRevLett.133.046502  

   Teng, Xiaokun; Tam, David_W; Chen, Lebing; Tan, Hengxin; Xie, Yaofeng; Gao, Bin; Granroth, Garrett_E; Ivanov, Alexandre; Bourges, Philippe; Yan, Binghai; et al (July 2024, Physical Review Letters)