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Observation of a Hard Correlation Gap in Quench-Condensed Ultrathin Beryllium

E. Bielejec·J. Ruan·Wenhao Wu
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Abstract

We report on the tunneling density of states (DOS) in ultrathin and strongly disordered Be films quench-condensed at 20 K. Above 5 K, the DOS shows the well-known logarithmic anomaly at the Fermi level. Only in a narrow temperature range near 2 K is the DOS linearly dependent on energy, as predicted by Efros and Shklovskii. However, both the zero-bias conductance and the slope of the linear DOS are found to decrease drastically with decreasing temperature. Tunneling measurements at mK temperatures have revealed conclusively that a hard correlation gap opens up in the DOS.

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E. Bielejec, J. Ruan, Wenhao Wu. 2000-08-23. Observation of a Hard Correlation Gap in Quench-Condensed Ultrathin Beryllium. https://doi.org/10.1103/physrevlett.87.036801

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