Bielejec E, Ruan J, Wu W. Hard correlation gap observed in quench-condensed ultrathin beryllium.
PHYSICAL REVIEW LETTERS 2001;
87:036801. [PMID:
11461578 DOI:
10.1103/physrevlett.87.036801]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2000] [Indexed: 05/23/2023]
Abstract
We report on the tunneling density of states (DOS) in strongly disordered ultrathin 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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