Direct Observation of the Hubbard Gap in a Semiconductor

Journal Article · Thu May 01 04:00:00 EDT 1997 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.78.3519· OSTI ID:496813

Dubon, O; Haller, E ^[1]; Dubon, O; Walukiewicz, W; Beeman, J; Haller, E ^[2]

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1. University of California, Berkeley, California 94720 (United States)
2. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

The transformation of the ground state of Cu acceptors in uniaxially stressed Ge from the (1s){sup 3} to the (1s){sup 2}(2s){sup 1} configuration results in a unique system in which a highly delocalized hole wave function corresponds to a relatively deep electronic state. This leads to electronic conduction via an isolated impurity band within the Ge band gap. By changing the Cu concentration we observe an evolution of the Hubbard gap for the 2s state from the full gap of 3.7meV at 3{times}10{sup 14}cm{sup -3} to zero gap at 1.6{times}10{sup 16}cm{sup -3}, in good agreement with our calculations. {copyright} {ital 1997} {ital The American Physical Society}

• Research Organization: Lawrence Berkeley National Laboratory
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 496813
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 18 Vol. 78; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COPPER ADDITIONS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRONIC STRUCTURE
ENERGY GAP
GERMANIUM
HUBBARD MODEL
STRESSES
TEMPERATURE DEPENDENCE