TY  - JOUR
AU  - Diego, Josu
AU  - Subires, D.
AU  - Said, Ayman
AU  - Chaney, D. A.
AU  - Korshunov, Artem
AU  - Garbarino, G.
AU  - Diekmann, F.
AU  - Mahatha, S. K.
AU  - Pardo, V.
AU  - Wilkinson, J. M.
AU  - Lord, J. S.
AU  - Strempfer, Joerg
AU  - Bereciartua Perez, Pablo Javier
AU  - Francoual, Sonia
AU  - Popescu, C.
AU  - Tallarida, M.
AU  - Dai, J.
AU  - Bianco, Raffaello
AU  - Monacelli, Lorenzo
AU  - Calandra, Matteo
AU  - BOSAK, Alexei
AU  - Mauri, Francesco
AU  - Rossnagel, Kai
AU  - Fumega, Adolfo O.
AU  - Errea, Ion
AU  - Blanco-Canosa, Santiago
TI  - Electronic structure and lattice dynamics of 1 T − VSe<sub>2</sub> : Origin of the three-dimensional charge density wave
JO  - Physical review / B
VL  - 109
IS  - 3
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - PUBDB-2024-00348
SP  - 035133
PY  - 2024
AB  - To characterize in detail the charge density wave (CDW) transition of 1 T − VSe<sub>2</sub>, its electronic structure and lattice dynamics are comprehensively studied by means of x-ray diffraction, muon spectroscopy, angle resolved photoemission (ARPES), diffuse and inelastic x-ray scattering, and state-of-the-art first-principles density functional theory calculations. Resonant elastic x-ray scattering does not show any resonant enhancement at either V or Se, indicating that the CDW peak at the K edges describes a purely structural modulation of the electronic ordering. ARPES experiments identify (i) a pseudogap at T > T<sub>CDW</sub>, which leads to a depletion of the density of states in the ML-M'L' plane at T > T<sub>CDW</sub>, and (ii) anomalies in the electronic dispersion reflecting a sizable impact of phonons on it. A diffuse scattering precursor, characteristic of soft phonons, is observed at room temperature (RT) and leads to the full collapse of the low-energy phonon (ω<sub>1</sub>) with propagation vector (0.25 0 −0.3) r.l.u. We show that the frequency and linewidth of this mode are anisotropic in momentum space, reflecting the momentum dependence of the electron-phonon interaction (EPI), hence demonstrating that the origin of the CDW is, to a much larger extent, due to the momentum dependent EPI with a small contribution from nesting. The pressure dependence of the ω<sub>1</sub> soft mode remains nearly constant up to 13 GPa at RT, with only a modest softening before the transition to the high-pressure monoclinic C2/m phase. The wide set of experimental data is well captured by our state-of-the art first-principles anharmonic calculations with the inclusion of van der Waals corrections in the exchange-correlation functional. The comprehensive description of the electronic and dynamical properties of VSe<sub>2</sub> reported here adds important pieces of information to the understanding of the electronic modulations in the family of transition-metal dichalcogenides. 
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001174196600011
DO  - DOI:10.1103/PhysRevB.109.035133
UR  - https://bib-pubdb1.desy.de/record/601655
ER  -