The low-temperature phase of : I. Angle and temperature dependence of the Shubnikov - de Haas and de Haas - van Alphen oscillations

House, A.A.; Haworth, C.; Caulfield, J.; Blundell, S. J.; Honold, M.M.; Singleton, John; Hayes, W.; Hayden, Stephen M; Meeson, P. J.; Springford, M; Kurmoo, Mohamedally; Day, Peter

doi:10.1088/0953-8984/8/49/026

Cited by 20 publications

(21 citation statements)

References 39 publications

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“…The breakdown is also manifest in enhanced SdH oscillations which are superposed on the semiclassical AMRO. A similar magnetic-breakdown induced crossover from the Q1D AMRO to the Q2D AMRO regime is well known for the ambient-pressure CDW state [30,31].…”

Section: Angle-dependent Magnetoresistance Oscillationssupporting

confidence: 67%

“…Moreover, it is known, that there is an anomalously strong second harmonic signal at 2F α as well as additional SdH frequencies at F λ = 170 T and F ν = F α + F λ , which only appear in the CDW state. The origin of these multiple frequencies is obviously related to the complex magnetic-breakdown network, although their detailed description is somewhat controversial [28,29,[31][32][33]. Under pressure, the magnitude of the magnetoresistance in Fig.…”

Section: Re-entrant Cdw State Under Pressurementioning

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 Oscillationssupporting

confidence: 67%

Section: Re-entrant Cdw State Under Pressurementioning

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 strong angular dependence of the interlayer magnetoresistance 10,17,22,25 implies that it is predominantly orbital in origin. When the field is parallel to the layers or at certain magic angles the magnetoresistance is several times smaller than when the field is perpendicular to the layers.…”

mentioning

confidence: 99%

Violation of Kohler’s rule by the magnetoresistance of a quasi-two-dimensional organic metal

et al. 1998

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The interlayer magnetoresistance of the quasi-two-dimensional metal ␣-͑BEDT-TTF͒ 2 KHg͑SCN͒ 4 is considered. In the temperature range from 0.5 to 10 K and for fields up to 10 T the magnetoresistance has a stronger temperature dependence than the zero-field resistance. Consequently Kohler's rule is not obeyed for any range of temperatures or fields. This means that the magnetoresistance cannot be described in terms of semiclassical transport on a single Fermi surface with a single scattering time. Possible explanations for the violations of Kohler's rule are considered, both within the framework of semiclassical transport theory and involving incoherent interlayer transport. The issues considered are similar to those raised by the magnetotransport of the cuprate superconductors. ͓S0163-1829͑98͒13219-8͔Currently a great deal of attention is being paid to the large magnetoresistance of layered materials such as magnetic multilayers 1 and manganese perovskites. 2 This is motivated by potential applications in magnetic recording and by the challenge of understanding the physical origin of the magnetoresistance, which is very different from that in conventional metals. 3 The magnetotransport of the metallic phase of the cuprate superconductors also differs significantly from conventional metals. [4][5][6] In this paper we show that the magnetoresistance of a particular organic metal may also be unconventional.Layered organic molecular crystals based on the bis͑ethylenedithia-tetrathiafulvalene͒ ͑BEDT-TTF͒ molecule are model low-dimensional electronic systems. 7,8 The family ␣-͑BEDT-TTF͒ 2 M Hg͑SCN͒ 4 [M ϭK,Rb,Tl͔ have a rich phase diagram depending on temperature, pressure, uniaxial stress, and magnetic field: metallic, superconducting, and density-wave phases are possible. 9-11 Band-structure calculations predict coexisting quasi-one-dimensional ͑open͒ and quasi-two-dimensional ͑closed͒ Fermi surfaces. 12 At ambient pressure these materials undergo a transition at a temperature T DW ͑8 K in the MϭK salt͒ into a low-temperature metallic phase that has been argued to be a density wave ͑DW͒. This phase is destroyed in high magnetic fields. There is currently controversy as to whether this phase is a spin-density wave, a charge-density wave, or a mixture of both. 9,[13][14][15][16] The following picture of the low-temperature phase has been proposed. 17,18 The nesting of the quasi-one-dimensional Fermi surface leads to a density-wave instability at T DW . Below T DW a gap opens on the quasi-one-dimensional Fermi surface and the associated carriers no longer contribute to the transport properties. The density wave introduces a new periodic potential into the system resulting in reconstruction of the quasi-two-dimensional Fermi surface. One of the proposed Fermi surface reconstructions involves large open sheets. 17 Semiclassical transport theory can then explain the large magnetoresistance and its angular dependence in the low-temperature phase. 18 The complete field dependence of the resistance can also be explained if ...

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“…Within the CDW 0 phase, dHvA measurements all agree that 0 *ϳ1.5. 2,8,[18][19][20]39 Within the CDW x phase, however, only one estimation of 0 *ϳ2.0 has been made that properly accounts for the effects of induced currents, now shown to occur in both static and pulsed magnetic fields. 5 Since ␣-(BEDT-TTF) 2 KHg(SCN) 4 is now believed to possess a CDW ground state of some form, [3][4][5]12,16 changes in 0 * between CDW subphases could be expected.…”

Section: Field Orientation Dependence Of the Dhva Phasementioning

confidence: 99%

Origin of the split quantum oscillation wave form inα−(BEDT−TTF)2KHg(SCN

et al. 2001

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We report the results of a detailed study of the field orientation dependence of the de Haas-van Alphen wave form in ␣-(BEDT-TTF) 2 KHg(SCN) 4 over a wide range of angles and fields. By considering the field orientation dependence of the sign and phase of the fundamental ␣ frequency, at fields both well above and below the kink transition field, it is found that the product of the effective mass with the electron g factor is approximately constant. This implies that spin splitting cannot occur within the low-magnetic-field phase until the angle between the magnetic field and the normal to the conducting planes is ϳ42°. This finding contrasts greatly with that recently published by Sasaki and Fukase. The results of the present study imply that the electron-electron interactions are largely field independent in this material, while a field dependence of the electron-phonon interactions is still tenable. The manner in which the amplitude of the wave form of the oscillations is damped within the low-magnetic-field phase is suggestive of a nonharmonically indexed reduction of the amplitude, thereby eliminating explanations in terms of magnetic breakdown or impurity scattering. Meanwhile, the presence of a large amplitude second harmonic within the low-magnetic-field phase that has a negative sign over a broad range of angles can be explained only by the frequency doubling effect.

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The low-temperature phase of : I. Angle and temperature dependence of the Shubnikov - de Haas and de Haas - van Alphen oscillations

Cited by 20 publications

References 39 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

Violation of Kohler’s rule by the magnetoresistance of a quasi-two-dimensional organic metal

Origin of the split quantum oscillation wave form inα−(BEDT−TTF)2KHg(SCN

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