Using angle-resolved photoemission spectroscopy, combined with first principle and coupled self-consistent Poisson-Schrödinger calculations, we demonstrate that potassium (K) atoms adsorbed on the low-temperature phase of 1T-TiSe_{2} induce the creation of a two-dimensional electron gas (2DEG) and quantum confinement of its charge-density wave (CDW) at the surface. By further changing the K coverage, we tune the carrier density within the 2DEG that allows us to nullify, at the surface, the electronic energy gain due to exciton condensation in the CDW phase while preserving a long-range structural order. Our Letter constitutes a prime example of a controlled exciton-related many-body quantum state in reduced dimensionality by alkali-metal dosing.
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http://dx.doi.org/10.1103/PhysRevLett.130.226401 | DOI Listing |
Phys Rev Lett
December 2024
Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan.
For over a century, the Hall effect, a transverse effect under an out-of-plane magnetic field or magnetization, has been a cornerstone for magnetotransport studies and applications. Modern theoretical formulation based on the Berry curvature has revealed the potential that even an in-plane magnetic field can induce an anomalous Hall effect, but its experimental demonstration has remained difficult due to its potentially small magnitude and strict symmetry requirements. Here, we report observation of the in-plane anomalous Hall effect by measuring low-carrier density films of magnetic Weyl semimetal EuCd_{2}Sb_{2}.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Science, Hangzhou 310024, China.
Size uniformity in colloidal quantum dots (CQDs) critically influences their electronic properties. However, achieving precise size control remains challenging for mercury chalcogenide systems. We demonstrate that a postsynthetic reheating treatment with the addition of dodecanethiol (DDT) ligands, consistent with a digestive ripening mechanism, effectively narrows the size distribution of HgTe CQDs from 12% to 6%, accompanied by enhanced crystallinity and sharper absorption features.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Research Institute for Electronic Science, Hokkaido University, Kita 20 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0020, Japan.
Nanoscale
November 2024
Jawaharlal Nehru Centre for Advanced Scientific Research, Theoretical Sciences Unit, Bangalore 560064, India.
Using first-principles theoretical analysis, we demonstrate the spin-polarized anomalous Hall conductivity (AHC) response of a 2D vdW heterostructure of graphene and ferromagnetic CrTe that can be controlled with a perpendicular electric field . The origins of AHC and linear magnetoelectric responses are traced to (a) the transfer of electronic charge from graphene to ferromagnetic CrTe causing an out-of-plane electric polarization = 1.69 μC cm and (b) the crystal field and spin-split Dirac points of graphene.
View Article and Find Full Text PDFNano Lett
November 2024
Department of Physics and Astronomy, University of California Riverside, Riverside, California 92521, United States.
Two-dimensional (2D) materials serve as exceptional platforms for controlled second-harmonic generation (SHG). Current approaches to SHG control often depend on nonresonant conditions or symmetry breaking via single-gate control. Here, we employ dual-gate bilayer WSe to demonstrate an SHG enhancement concept that leverages strong exciton resonance and a layer-dependent exciton-polaron effect.
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