Pressure dependence of superconductivity in Ba{sub 4}C{sub 60}
- Technische Hochschule Darmstadt (Germany); and others
In Ba{sub x}C{sub 60} superconductivity (sc) at T{sub c} = (6.8{+-}0.2) K is associated with the x=4 phase. Here the authors present pressure studies of T{sub c} of a Ba{sub x}C{sub 60} sample (dT{sub c}/dp= {minus}1.9 K/GPa) which exhibits a large volume fraction of the x=4 phase. In the alkali-fullerides K{sub 3}C{sub 60} and Rb{sub 3}C{sub 60} T{sub c} is governed by the electronic density of states N(E{sub F}) (T{sub c} {proportional_to}exp{minus}1/N(E{sub F})V). The dependence of N(E{sub F}) on volume can be approximated by N(E{sub F})=N{sub 0}d{sub eff}{sup 3} where d{sub eff} is the surface to surface distance of neighboured C{sub 60}-molecules. This relationship is corroborated by (T{sub c}, d)-data of various compounds of the form A{sub 3{minus}x}B{sub x}C{sub 60} (A: K, Rb; B: K, Rb, Cs; x{le}2). Strong deviation from this behavior is found for the alkaline-fulleride superconductor Ba{sub 4}C{sub 60}. This deviation is attributed to the hybridization of alkaline-metal s-, d-states and C{sub 60} {pi}-states.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 443721
- Report Number(s):
- CONF-960808--; CNN: Contract 13 N 6172 (THD); Contract 13 N 6074 (FUB)
- Journal Information:
- Journal of Low Temperature Physics, Journal Name: Journal of Low Temperature Physics Journal Issue: 5-6 Vol. 105; ISSN JLTPAC; ISSN 0022-2291
- Country of Publication:
- United States
- Language:
- English
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