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NM Zimmerman

Publications and source records attributed to NM Zimmerman.

7 recordsLinked to original sources

Electrical conductivity of xenon at megabar pressures

The electrical transport properties of solid xenon were directly measured at pressures up to 155 GPa and temperatures from 300 K to 27 mK. The temperature dependence of resistance changed from semiconducting to metallic at pressures between 121 and 138 GPa, revealing direct proof of metallization of a rare-gas solid by electrical transport measurements. Anomalies in the conductivity are observed at low temperatures in the vicinity of the transition such that purely metallic behavior is observed only at 155 GPa over the entire temperature range.

Journal Article↗

A capacitance standard based on counting electrons

A capacitance standard based directly on the definition of capacitance was built. Single-electron tunneling devices were used to place N electrons of charge e onto a cryogenic capacitor C, and the resulting voltage change DeltaV was measured. Repeated measurements of C = Ne/DeltaV with this method have a relative standard deviation of 0.3 x 10(-6). This standard offers a natural basis for capacitance analogous to the Josephson effect for voltage and the quantum Hall effect for resistance.

Journal Article↗