Pressure induced suppression of the singlet insulator phase in BaVS$_3$: infrared optical study

I. Kézsmárki; G. Mihály; R. Gaál; N. Barišić; H. Berger; L. Forró; C. C. Homes; L. Mihály

doi:10.1103/PhysRevB.71.193103

paper

Pressure induced suppression of the singlet insulator phase in BaVS $_{3}$ : infrared optical study

arXiv:cond-mat/0311335 · doi:10.1103/PhysRevB.71.193103

Abstract

The metal-insulator (MI) transition in BaVS $_{3}$ has been studied at ambient pressure and under hydrostatic pressure up to $p = 26$ kbar in the frequency range of $20 - 3000$ cm $^{- 1}$ . The charge gap determined from the optical reflectivity is enhanced, $Δ_{c h} (p) / k_{B} T_{M I} (p) \sim 12$ . This ratio is independent of pressure indicating that the character of the transition does not vary along the $p - T$ phase boundary. Above the critical pressure, $p_{cr} \sim 20$ kbar, metallic spectra were recorded in the whole temperature range, as expected from the shape of the phase diagram. Our results exclude the opening of a pseudogap above $T_{M I}$ at any pressure. Below $T_{M I}$ an unusually strong temperature dependence of the charge gap was observed, resulting in a $Δ_{c h} (T)$ deviating strongly from the mean field-like variation of the structural order parameter.

5 pages, 3 figures. to be published

References in corpus (1)

Charge Ordering Fluctuation and Optical Pseudogap in La $_{1 - x}$ Ca $_{x}$ MnO $_{3}$

Pressure induced suppression of the singlet insulator phase in BaVS3​: infrared optical study

Abstract

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Pressure induced suppression of the singlet insulator phase in BaVS $_{3}$ : infrared optical study