Exploring the charge-ordering transition in (TMTTF)2X via thermal expansion measurements

被引：16

作者：

de Souza, Mariano ^{[1
]}

Hofmann, Daniel ^{[1
]}

Foury-Leylekian, Pascale ^{[2
]}

Moradpour, Alec ^{[2
]}

Pouget, Jean-Paul ^{[2
]}

Lang, Michael ^{[1
]}

机构：

[1] Goethe Univ Frankfurt, Inst Phys, D-60438 Frankfurt, Germany

[2] Univ Paris 11, Phys Solides Lab, CNRS, UMR 8502, F-91405 Orsay, France

来源：

PHYSICA B-CONDENSED MATTER | 2010年 / 405卷 / 11期

关键词：

Charge-ordering transition; Ferroelectricity; Thermal-expansion; Organic conductors; MOTT-HUBBARD PHASE; ORGANIC CONDUCTORS; FAMILY; SALTS;

D O I：

10.1016/j.physb.2009.12.022

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

We report results of high-resolution measurements of the c-axis expansivity (x(c)) at the charge-ordering (CO) transition for the quasi-1D (TMTTF)(2)X compounds with X = SbF6 and Br and make a comparison with previous results for the X = PF6 and AsF6 salts For X = SbF6 due to the screening of the long-range Coulomb forces a sharp lambda-type anomaly is observed at T-CO which contrasts with the step-like mean-field anomaly at T-CO for PF6 and AsF6 where CO occurs in the Mott-Hubbard charge-localized regime For the latter two salts a negative contribution to alpha(c) is observed above T-CO This feature is assigned to the anions rigid-unit modes which become inactive for T < T-CO Our x(c) results for the X = Br salt where such rigid-unit modes are absent reveal no traces of such negative contribution confirming the model based on the anions rigid-unit modes for the X = PF6 and AsF6 salts (C) 2009 Elsevier B V All rights reserved

引用

页码：S92 / S94

页数：3

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