Pressure-dependent metallic and superconducting phases in a germanium artificial metal.
Germanium (Ge) becomes an "artificial metal" and a superconductor (T(c) approximately 5 K) above the pressure-induced semiconductor-(diamond structure)-to-metal (beta-Sn structure) transition at 10 GPa. We report single crystal resistance studies of the pressure-dependent metallic and metastable phases in the range 2.6 to 23 GPa, and show for a controlled pressure release, Ge is a metastable metal below 3 GPa. We find Ge has a superconducting upper critical field of 300 Oe (at 10.7 GPa and 1.8 K), above which a positive magnetoresistance consistent with that of a compensated closed orbit metal is observed.
Cui
H B
HB
Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA.
Graf
D
D
Brooks
J S
JS
Kobayashi
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H