We have measured the change in the fundamental Shubnikov-de Haas (SdH) frequency of (ET)
2TlHg(SCN)
4 in the pressure range 0–5.0 GPa. We find that the SdH frequency increases linearly in the ...pressure range 0–3.0 GPa with
dF
dP
= 110±20
T/GPa
; at pressures above 3.0 GPa, however, the fundamental frequency drops drastically — roughly by a factor of three — suggesting that a pressure induced change in the bandstructure has occurred.
Systematic magnetotransport measurements as a function of hydrostatic pressure have been made on four members of the α-(BEDT-TTF)
2MHg(SCN)
4 organic conductor family (M = K, Tl, Rb, NH
4). Applied ...pressure above about 6 Kbar removes the density wave state for M = K, Tl, and Rb. For M = NH
4 the superconducting state is removed with pressure as
dT
c
dP
= − 0.25
K/Kbar
. In all cases the Shubnikov de Haas oscillation frequency increases with pressure, including the β orbit (which involves the entire Brillouin zone), and new orbits involving very small fractions of the Fermi surface are formed.
We have studied the temperature dependence of the integer quantum Hall
transitions in the molecular crystal (TMTSF)$_2$PF$_6$. We find that the
transition width between the quantum Hall plateaus does ...not exhibit the
universal power-law scaling behavior of the integer quantum Hall effect
observed in semiconducting devices. Instead, the slope of the $\rho_{xy}$
risers, $d\rho_{xy}/dB$, and the (inverse) width of the $\rho_{xx}$ peaks,
$(\Delta B)^{-1}$, show a BCS-like energy gap temperature dependence. We
discuss these results in terms of the field-induced spin-density wave gap and
order parameter of the system.
We have studied the temperature dependence of the integer quantum Hall transitions in the molecular crystal (TMTSF)\(_2\)PF\(_6\). We find that the transition width between the quantum Hall plateaus ...does not exhibit the universal power-law scaling behavior of the integer quantum Hall effect observed in semiconducting devices. Instead, the slope of the \(\rho_{xy}\) risers, \(d\rho_{xy}/dB\), and the (inverse) width of the \(\rho_{xx}\) peaks, \((\Delta B)^{-1}\), show a BCS-like energy gap temperature dependence. We discuss these results in terms of the field-induced spin-density wave gap and order parameter of the system.
Old Icelandic, an Introductory Course Lamberts, J. J.
Rocky Mountain Review of Language and Literature,
01/1982, Letnik:
36, Številka:
4
Book Review, Journal Article
PDF
