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Foury-Leylekian, P.; Pouget, Jean‐Paul; Lee, Young‐Joo; Nieminen, Risto M.; Ordejón, Pablo; Canadell, Enric

doi:10.1103/physrevb.82.134116

Cited by 26 publications

(37 citation statements)

References 76 publications

(110 reference statements)

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“…The latter originates from cyclotron motion of charge carriers on a slightly warped cylindrical Fermi surface [59][60][61][62][63]. Indeed, the Fermi surface of α-(BEDT-TTF) 2 KHg(SCN) 4 accommodates a hole cylinder in addition to the pair of electron open sheets [13,64]. At low temperatures and ambient pressure, i.e., in the CDW state the magnetoresistance is very high at B perpendicular to layers and shows a regular series of sharp dips at tilting the field.…”

Section: Angle-dependent Magnetoresistance Oscillationsmentioning

confidence: 99%

“…The layered organic metal α-(BEDT-TTF) 2 KHg(SCN) 4 undergoes a phase transition into a charge-density-wave (CDW) state at T CDW ≈ 8.5 K at ambient pressure [9][10][11][12][13]. A Q1D electron band becomes gapped at the Fermi level, due to the so-called nesting of the Fermi surface, while the other, quasi-two-dimensional (Q2D) band still determines a metallic character of the system.…”

Section: Introductionmentioning

confidence: 99%

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Field-induced charge-density-wave transitions in the organic metal α-(BEDT-TTF)2KHg(SCN)4 under pressure

Andres

Kartsovnik

Biberacher

et al. 2011

Low Temperature Physics

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Successive magnetic-field-induced charge-density-wave transitions in the layered molecular conductor α-(BEDT-TTF) 2 KHg(SCN) 4 are studied in the hydrostatic pressure regime, in which the zero field chargedensity-wave (CDW) state is completely suppressed. The orbital effect of the magnetic field is demonstrated to restore the density wave, while the orbital quantization induces transitions between different CDW states at changing the field strength. The latter appear as distinct anomalies in the magnetoresistance as a function of field. The interplay between the orbital and Pauli paramagnetic effects acting, respectively, to enhance and to suppress the CDW instability is particularly manifest in the angular dependence of the field-induced anomalies.

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Section: Angle-dependent Magnetoresistance Oscillationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Field-induced charge-density-wave transitions in the organic metal α-(BEDT-TTF)2KHg(SCN)4 under pressure

Andres

Kartsovnik

Biberacher

et al. 2011

Low Temperature Physics

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“…The satellite reflections are already detected at high temperature (250-300 K). Recently, they pointed out the anion sublattice instability leading to deformation of the SCN tetrahedral coordination of Hg 2+ and SCN tetragonal antiprismatic coordination of K + in α-KHg [147]. They claimed that the Fermi-surface-nesting instability of the BEDT-TTF layer is coupled with the instability of the anion sublattice.…”

Section: Fluctuation Of Charge Order In Metallic Phasementioning

confidence: 99%

“…Table 4 shows the site-charge distribution of α-NH 4 Hg calculated by the mean-field approximation with the transfer integrals given by Mori et al [142] and Coulomb interaction parameters, U = 0.4, V c = 0.17, V p = 0.05 eV [157]. Foury-Leylekian et al, calculated the band structure of isostructural α-KHg at 104 K using a numerical atomic orbital DFT approach, and presented the site charges [147]. Their values are shown in Table 4 along with the hole numbers of isostructural compounds, α-MHg (M = K, Rb, Rl).…”

Section: Site Charge Distribution In Metallic Phase At Ambient Pressurementioning

confidence: 99%

Infrared and Raman Studies of Charge Ordering in Organic Conductors, BEDT-TTF Salts with Quarter-Filled Bands

Yakushi

2012

Crystals

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This paper reviews charge ordering in the organic conductors, β″-(BEDT-TTF) (TCNQ), θ-(BEDT-TTF) 2 X, and α-(BEDT-TTF) 2 X. Here, BEDT-TTF and TCNQ represent bis(ethylenedithio)tetrathiafulvalene and 7,7,8,8-tetracyanoquinodimethane, respectively. These compounds, all of which have a quarter-filled band, were evaluated using infrared and Raman spectroscopy in addition to optical conductivity measurements. It was found that β″-(BEDT-TTF)(TCNQ) changes continuously from a uniform metal to a chargeordered metal with increasing temperature. Although charge disproportionation was clearly observed, long-range charge order is not realized. Among six θ-type salts, four compounds with a narrow band show the metal-insulator transition. However, they maintain a large amplitude of charge order (Δρ~0.6) in both metallic and insulating phases. In the X = CsZn(SCN) 4 salt with intermediate bandwidth, the amplitude of charge order is very small (Δρ < 0.07) over the whole temperature range. However, fluctuation of charge order is indicated in the Raman spectrum and optical conductivity. No indication of the fluctuation of charge order is found in the wide band X = I 3 salt. In α-(BEDT-TTF) 2 I 3 the amplitude of charge order changes discontinuously from small amplitude at high temperature to large amplitude (Δρ max~0 .6) at low temperature. The long-range chargeordered state shows ferroelectric polarization with fast optical response. The fluctuation of multiple stripes occurs in the high-temperature metallic phase. Among α-(BEDT-TTF) 2 MHg(SCN) 4 (X = NH 4 , K, Rb, Tl), the fluctuation of charge order is indicated only in the X = NH 4 salt. α′-(BEDT-TTF) 2 IBr 2 shows successive phase transitions to the ferroelectric state keeping a large amplitude of charge order (Δρ max~0 .8) over the whole temperature range. It was found that the amplitude and fluctuation of charge order in these compounds is enhanced as the kinetic energy (bandwidth) decreases. OPEN ACCESSCrystals 2012, 2 1292

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“…At temperature T ∼ 10 K three salts, with M = K, Tl, and Rb, and X = S undergo a charge-density-wave (CDW) transition caused by the Peierls-type nesting instability of the open Fermi sheets [7,21]. The compounds remain, however, metallic due to the ungapped cylindrical Fermi surface.…”

Section: Introductionmentioning

confidence: 99%

Magnetic quantum oscillations in the charge-density-wave state of the organic metals α-(BEDT-TTF)2MHg(SCN)4 with M = K and Tl

Kartsovnik

Zverev

Andres

et al. 2014

Low Temperature Physics

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The low-temperature charge-density-wave (CDW) state in the layered organic metals α-(BEDT-TTF) 2 MHg(SCN) 4 has been studied by means of the Shubnikov -de Haas and de Haas -van Alphen effects. In addition to the dominant α-frequency, which is also observed in the normal state, both the magnetoresistance and magnetic torque possess a slowly oscillating component. These slow oscillations provide a firm evidence for the CDW-induced reconstruction of the original cylindrical Fermi surface. The α-oscillations of the interlayer magnetoresistance exhibit an anomalous phase inversion in the CDW state, whereas the de Haas -van Alphen signal maintains the normal phase. We argue that the anomaly may be attributed to the magneticbreakdown origin of the α-oscillations in the CDW state. A theoretical model illustrating the possibility of a phase inversion in the oscillating interlayer conductivity in the presence of a spatially fluctuating magnetic breakdown gap is proposed.

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Density-wave instability inα−(BEDT-TTF)2KHg(SCN)4

Cited by 26 publications

References 76 publications

Field-induced charge-density-wave transitions in the organic metal α-(BEDT-TTF)2KHg(SCN)4 under pressure

Field-induced charge-density-wave transitions in the organic metal α-(BEDT-TTF)2KHg(SCN)4 under pressure

Infrared and Raman Studies of Charge Ordering in Organic Conductors, BEDT-TTF Salts with Quarter-Filled Bands

Magnetic quantum oscillations in the charge-density-wave state of the organic metals α-(BEDT-TTF)2MHg(SCN)4 with M = K and Tl

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