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Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials

Abstract

During this PhD project, the metal-insulator transition and superconductivity of highly boron-doped single crystal diamond and related materials have been investigated. The critical boron concentration n{sub c} for the metal-insulator transition was found to be the same as for the normal-superconductor transition. All metallic samples have been found to be superconducting and we were able to link the occurence of superconductivity to the proximity to the metal-insulator transition. For this purpose, a scaling law approach based on low temperature transport was proposed. Furthermore, we tried to study the nature of the superconductivity in highly boron doped single crystal diamond. Raman spectroscopy measurements on the isotopically substituted series suggest that the feature occuring at low wavenumbers ({approx} 500 cm{sup -1}) is the A1g vibrational mode associated with boron dimers. Usual Hall effect measurements yielded a puzzling situation in metallic boron-doped diamond samples, leading to carrier concentrations up to a factor 10 higher than the boron concentration determined by secondary ion mass spectroscopy (SIMS). The low temperature transport follows the one expected for a granular metal or insulator, depending on the interplay of intergranular and intragranular (tunneling) conductance. The metal-insulator transition takes place at a critical conductance g{sub c}. The granularity also  More>>
Authors:
Publication Date:
May 15, 2009
Product Type:
Thesis/Dissertation
Report Number:
INIS-DE-0735
Resource Relation:
Other Information: TH: Diss. (Dr.rer.nat.); Related Information: Selected Topics of Semiconductor Physics and Technology v. 108
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; SUPERCONDUCTIVITY; BORON ADDITIONS; DIAMONDS; MONOCRYSTALS; HALL EFFECT; COUPLING; PHONONS; PLASMONS; SILICON CARBIDES; PHASE TRANSFORMATIONS; DOPED MATERIALS; RAMAN SPECTRA; GRANULAR MATERIALS; ALUMINIUM ADDITIONS; THIN FILMS; FCC LATTICES; SILICON; ENERGY GAP
OSTI ID:
21209275
Research Organizations:
Technische Univ. Muenchen, Garching (Germany). Walter-Schottky-Inst. fuer Physikalische Grundlagen der Halbleiterelektronik; Grenoble-1 Univ., 38 (France). Inst. Fourier; Technische Univ. Muenchen, Garching (Germany). Fakultaet fuer Physik
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
Other: ISBN 978-3-941650-08-4; TRN: DE09F8835
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21209275
Submitting Site:
DEN
Size:
170 pages
Announcement Date:
Sep 02, 2009

Citation Formats

Achatz, Philipp. Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials. Germany: N. p., 2009. Web.
Achatz, Philipp. Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials. Germany.
Achatz, Philipp. 2009. "Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials." Germany.
@misc{etde_21209275,
title = {Metal-insulator transition and superconductivity in heavily boron-doped diamond and related materials}
author = {Achatz, Philipp}
abstractNote = {During this PhD project, the metal-insulator transition and superconductivity of highly boron-doped single crystal diamond and related materials have been investigated. The critical boron concentration n{sub c} for the metal-insulator transition was found to be the same as for the normal-superconductor transition. All metallic samples have been found to be superconducting and we were able to link the occurence of superconductivity to the proximity to the metal-insulator transition. For this purpose, a scaling law approach based on low temperature transport was proposed. Furthermore, we tried to study the nature of the superconductivity in highly boron doped single crystal diamond. Raman spectroscopy measurements on the isotopically substituted series suggest that the feature occuring at low wavenumbers ({approx} 500 cm{sup -1}) is the A1g vibrational mode associated with boron dimers. Usual Hall effect measurements yielded a puzzling situation in metallic boron-doped diamond samples, leading to carrier concentrations up to a factor 10 higher than the boron concentration determined by secondary ion mass spectroscopy (SIMS). The low temperature transport follows the one expected for a granular metal or insulator, depending on the interplay of intergranular and intragranular (tunneling) conductance. The metal-insulator transition takes place at a critical conductance g{sub c}. The granularity also influences significantly the superconducting properties by introducing the superconducting gap {delta} in the grain and Josephson coupling J between superconducting grains. A peak in magnetoresistance is observed which can be explained by superconducting fluctuations and the granularity of the system. Additionally we studied the low temperature transport of boron-doped Si samples grown by gas immersion laser doping, some of which yielded a superconducting transition at very low temperatures. Furthermore, preliminary results on the LO-phonon-plasmon coupling are shown for the first time in aluminum-doped 4H SiC by Raman spectroscopy. (orig.)}
place = {Germany}
year = {2009}
month = {May}
}