X-ray structural study of 4k_F Wigner crystal and 4k_F Peierls state in DCNQI complex with 1/4 filled quasi one-dimensional band

Bond and charge-density waves in(DI−DCNQI)2Ag(DI−DCNQIYamamoto1, Yamamoto2, Yakushi3 et al. 2005Phys. Rev. B13241View full textAdd to dashboardCite

“…Since the EMV interaction is very sensitive to local structural modulation, the EMV bands, which reflect a local bro- ken symmetry, are usually present far above the phase transition. 32 This is in accord with the x-ray diffraction data, which shows intense 4k F streaks already at RT, 33 which is a clear indication that dimerization has already occurred. These 4k F streaks have been attributed to the 1010 type of CO (4k F CDW ͓Fig 4͑c͔͒), but the IR data clearly show that the structure must be a 4k F BOW ͓Fig.…”

“…The complex eventually enters into an antiferromagnetic ͑AF͒ state below 5.5 K in spite of the highly 1D structure. 7, 8 Hiraki and Kanoda examined the 13 C-NMR spectrum of the same complex and found that the NMR signal splits into two independent signals below approximately 220 K. 2 They reported that the splitting of the signal is representative of CD, with the localized charges arranged in a 1010 manner ͑1 and 0 denote charge rich and poor sites, crespectively͒. This interpretation was consistent with the result of Seo-Fukuyama's theoretical calculation, which takes into account the nearest neighbor Coulomb interaction V in the Hubbard model 9 and which predicted that the charge would localize in the 1010 manner when V is over a critical value.…”

“…13 This modulation has been characterized as a CDW and is described by 1010 CO structure without a parallel 4k F BOW. On the other hand, Meneghetti FIG et al have suggested that there is a certain molecular displacement in DI 2 -Ag based on the finding of strong bands related to electron-molecular vibration ͑EMV͒ coupling of a g vibrational modes with charge transfer excitation in the powder infrared ͑IR͒ spectrum.…”

Dielectric response of the charge-induced correlated state in the quasi-one-dimensional conductor(TMTTF)2PF6

“…On the contrary, we argue that this large dielectric polarizability reflects the collective response of 4k F charge density wave of Wigner crystal type due to long range Coulomb interaction and electron-electron correlation. Recently charge disproportionation [23] and 4k F superlattice [24] have been reported from NMR and X-ray measurements in a 1/4 filled one-dimensional organic compound (DI-DCNQI) 2 Ag without dimerization.…”

Knight Shift and Nuclear Spin Relaxation Rate in a Charge-Ordered State of the One-Dimensional Extended Hubbard Model at Quarter Filling

“…Thus, the materials are one of the most suitable systems for studying exotic states realized by the interaction between electrons in low dimensional systems. Recently, the remarkable state with inhomogeneous but regular charge arrangement called as the charge ordering (CO) has been found in the organic materials with 2:1 composition ratio A 2 B, such as (DI-DCNQI) 2 Ag, [2][3][4] (TMTTF) 2 X 5-8 and (BEDT-TTF) 2 X 9-14 with X being a monovalent anion. Since the molecule B is ionized as B + or B − in order to form a closed shell, the average valence of A becomes −1/2 or +1/2.…”