The low-temperature phase of : II. Pressure dependence of the Shubnikov - de Haas oscillations

Abstract

The magnetoresistance of (where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene and or K) has been studied under pressures of up to 14.8 kbar and for temperatures down to 0.7 K. The and Shubnikov - de Haas oscillations observed in the ambient pressure magnetoresistance of persist to the highest pressure while the other quantum oscillatory frequencies are removed under pressure. A strong second-harmonic component of the -frequency oscillations is observed on the raw data at 1 bar and is initially suppressed by pressure but returns above . Furthermore, in the salt a similar pronounced second harmonic of the quantum oscillations has been observed at the highest pressures. The origins of these features of the data are discussed in the context of current models of the Fermi surfaces of these materials.

Frequency combinations in the magnetoresistance oscillations spectrum of a linear chain of coupled orbits with a high scattering rate

“…In contrast, Eq. 5 is in full agreement with the data of 2α (see Table 1) as it has already been reported for the 2α [5,24] and 2β [25] components observed in magnetoresistance data of other linear chains of orbits. However, according to the data of Table 1, neither Eq.…”

Studies of quasi-two-dimensional organic conductors based on BEDT-TTF using high magnetic fields

“…However, there is some evidence that a lower frequency (∼47 T) series of weak quantum oscillation is present in the magnetoresistance of this salt at ambient pressure [205]. The authors of [205] pointed out the similarity of these data to the apparent lowfrequency SdH oscillations observed in α-(BEDT-TTF) 2 NH 4 Hg(SCN) 4 under high hydrostatic pressures [207] (see section 4.7.3), suggesting that the oscillations might indicate the formation of a density-wave state.…”

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

“…This paper is the first of a series of two, the second of which will report on measurements of the SdH effect in both α-(BEDT-TTF) 2 KHg(SCN) 4 and α-(BEDT-TTF) 2 NH 4 Hg(SCN) 4 when hydrostatic pressure is applied [23]. Throughout these articles we shall refer to the present paper as I and the following one as II.…”