Pressure-induced changes in the optical properties of quasi-one-dimensionalβ−Na0.33V2O5

Abstract

The pressure-induced changes in the optical properties of β-Na0.33V2O5 single crystals at room temperature were studied by polarization-dependent Raman and far-infrared reflectivity measurements under high pressure. From the changes in the Raman-and infrared-active phonon modes in the pressure range 9 -12 GPa a transfer of charge between the different V sites can be inferred. The importance of electron-phonon coupling in the low-pressure regime is discussed.

The peculiar structural behaviour of β-Na0.33V2O5 upon electrochemical lithium insertion

“…These Raman data are the first reported for b-Na 0.33 V 2 O 5 powder, previous Raman studies dealing with b-Na 0.33 V 2 O 5 single crystals. 15 A partial assignment of the Raman modes has been previously proposed from a comparison with polarized Raman data on the closely related compound b-Ca 0.33 V 2 O 5 16 (see Table 3). Both b-Ca 0.33 V 2 O 5 and b-Na 0.33 V 2 O 5 crystallize in the same monoclinic crystal structure, with a doubling of the unit cell in b-Ca 0.33 V 2 O 5 along the b direction due to an ordering of the Ca atoms.…”

“…Room temperature Raman modes of b-Na 0.33 V 2 O 5 powder with those of b-Ca 0.33 V 2 O 516 and b-Na 0.33 V 2 O 515 single crystals reported for comparison, and their assignments to particular V-O stretching modes in the V(O) 6 and V(O) 5 polyhedra…”

Exploring the coordination change of vanadium and structure transformation of metavanadate MgV2O6 under high pressure

“…A “devil’s staircase”-type phase transition in the quarter-filled spin-ladder compound NaV 2 O 5 has been discovered at low temperature and high pressure28. Interestingly, the pressure-induced superconductivity has been found in β - X + 0.33 V 2 O 5 ( X +  = Li, Na, and K) but absent in β - X 2 + 0.33 V 2 O 5 ( X 2 +  = Ca, Sr, and Pb), although a charge order transition existed in all these compounds except β -Pb 0.33 V 2 O 5 29303132.…”

Infrared and Terahertz Spectroscopy of Strongly Correlated Electron Systems under Extreme Conditions

“…β-vanadium bronze (β-Na 0.33 V 2 O 5 ), which is a pressure-induced, one-dimensional superconductor with T c = 8 K above 8 GPa, was also studied by IR-SR spectroscopy up to 20 GPa. 88,89 3.4 Organic compounds under high Pressure Organic metals and semiconductors exhibit a rich variety of physical phenomena under high pressure. For example, the IR reflectance of the pressure-induced superconductor (TMTSF) 2 PF 6 and the charge-ordering insulator (TMTTF) 2 PF 6 under high pressure have been studied using DAC and IR-SR. 90 For 2D organic conductor κ-(ET) 2 Cu[N(CN) 2 ]X (X = Br, Cl), detailed infrared spectroscopic imaging studies have been performed under high pressure.…”

“…-vanadium bronze ( -Na 0:33 V 2 O 5 ), which is a pressure-induced, one-dimensional superconductor with T c ¼ 8 K above 8 GPa, was also studied by IR-SR spectroscopy up to 20 GPa. 88,89) …”