In the optical conductivity of four different manganites with commensurate charge order (CO), strong peaks appear in the meV range below the ordering temperature T_{CO}. They are similar to those reported for one-dimensional charge density waves (CDW) and are assigned to pinned phasons. The peaks and their overtones allow one to obtain, for La_{1-n/8}Ca_{n/8}MnO_{3} with n=5, 6, the electron-phonon coupling, the effective mass of the CO system, and its contribution to the dielectric constant. These results support a description of the CO in La-Ca manganites in terms of moderately weak coupling and of the CDW theory.
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http://dx.doi.org/10.1103/PhysRevLett.101.066407 | DOI Listing |
Nano Lett
January 2025
Department of Quantum Matter Physics, University of Geneva, 24, Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
Tunable electronic properties in transition metal dichalcogenides (TMDs) are essential to further their use in device applications. Here, we present a comprehensive scanning tunneling microscopy and spectroscopy study of a doping-induced charge density wave (CDW) in semiconducting bulk 1T-ZrSe. We find that atomic impurities that locally shift the Fermi level () into the conduction band trigger a CDW reconstruction concomitantly to the opening of a gap at .
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics, Stanford University, Stanford, California 94305, USA.
Inspired by the observation of increasingly one-dimensional (1D) behavior with decreasing temperature in small-angle twisted bilayers of WTe_{2} (tWTe_{2}), we theoretically explore the exotic sliding regimes that could be realized in tWTe_{2}. At zero displacement field, while hole-doped tWTe_{2} can be thought of as an array of weakly coupled conventional two-flavor 1D electron gases (1DEGs), the electron-doped regime is equivalent to coupled four-flavor 1DEGs, due to the presence of an additional "valley" degree of freedom. In the decoupled limit, the electron-doped system can thus realize phases with a range of interesting ordering tendencies, including 4k_{F} charge-density-wave and charge-4e superconductivity.
View Article and Find Full Text PDFNat Commun
January 2025
Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China.
Unconventional superconductivity is known for its intertwining with other correlated states, making exploration of the intertwined orders important for understanding its pairing mechanism. In particular, spin and nematic orders are widely observed in iron-based superconductors; however, the presence of charge order is uncommon. Using scanning tunnelling microscopy, and through expanding the phase diagram of iron-arsenide superconductor BaKFeAs to the hole-doping regime beyond KFeAs by surface doping, we demonstrate the formation of a charge density wave (CDW) on the arsenide surface of heavily hole-doped BaKFeAs.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe, Germany.
We present a high-resolution single crystal x-ray diffraction study of kagome superconductor CsV_{3}Sb_{5}, exploring its response to variations in pressure and temperature. We discover that at low temperatures, the structural modulations of the electronic superlattice, commonly associated with charge-density-wave order, undergo a transformation around p∼0.7 GPa from the familiar 2×2 pattern to a long-range-ordered modulation at wave vector q=(0,3/8,1/2).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996.
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