TY - JOUR
T1 - Metal-insulator transition in the low-dimensional organic conductor (TMTSF) 2FSO 3 probed by infrared microspectroscopy
AU - Pashkin, A.
AU - Thirunavukkuarasu, K.
AU - Mathis, Y. L.
AU - Kang, W.
AU - Kuntscher, C. A.
PY - 2007/4
Y1 - 2007/4
N2 - We present measurements of the infrared response of the quasi-one-dimensional organic conductor (TMTSF) 2FSO 3 along (E∥a) and perpendicular (E∥b') to the stacking axis as a function of temperature. Above the metal-insulator transition related to the anion ordering the optical conductivity spectra show a Drude-like response. Below the transition an energy gap of about 1500 cm -1 (185 meV) opens, leading to the corresponding charge transfer band in the optical conductivity spectra. The analysis of the infrared-active vibrations gives evidence for the long-range crystal structure modulation below the transition temperature and for the short-range order fluctuations of the lattice modulation above the transition temperature. We also report about a new infrared mode at around 710 cm-1 with a peculiar temperature behavior, which has so far not been observed in any other (TMTSF) 2X salt showing a metal-insulator transition. A qualitative model based on the coupling between the TMTSF molecule vibration and the reorientation of electrical dipole moment of the FSO 3 anion is proposed, in order to explain the anomalous behavior of this new mode.
AB - We present measurements of the infrared response of the quasi-one-dimensional organic conductor (TMTSF) 2FSO 3 along (E∥a) and perpendicular (E∥b') to the stacking axis as a function of temperature. Above the metal-insulator transition related to the anion ordering the optical conductivity spectra show a Drude-like response. Below the transition an energy gap of about 1500 cm -1 (185 meV) opens, leading to the corresponding charge transfer band in the optical conductivity spectra. The analysis of the infrared-active vibrations gives evidence for the long-range crystal structure modulation below the transition temperature and for the short-range order fluctuations of the lattice modulation above the transition temperature. We also report about a new infrared mode at around 710 cm-1 with a peculiar temperature behavior, which has so far not been observed in any other (TMTSF) 2X salt showing a metal-insulator transition. A qualitative model based on the coupling between the TMTSF molecule vibration and the reorientation of electrical dipole moment of the FSO 3 anion is proposed, in order to explain the anomalous behavior of this new mode.
UR - http://www.scopus.com/inward/record.url?scp=34249688490&partnerID=8YFLogxK
U2 - 10.1140/epjb/e2007-00121-8
DO - 10.1140/epjb/e2007-00121-8
M3 - Article
AN - SCOPUS:34249688490
SN - 1434-6028
VL - 56
SP - 285
EP - 290
JO - European Physical Journal B
JF - European Physical Journal B
IS - 4
ER -