Complete scaling analysis of the metal-insulator transition in Ge: Ga: Effects of doping-compensation and magnetic field

Kohei M Itoh, Michio Watanabe, Youiti Ootuka, Eugene E. Haller, Tomi Ohtsuki

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

We report on the complete scaling analysis of low temperature electron transport properties with and without magnetic field in the critical regime for the metal-insulator transition in two series of homogeneously doped p-type Ge samples: i) nominally uncompensated neutron-transmutation-doped (NTD) 70Ge:Ga samples with the technological compensation ratio K < 0.001, and ii) intentionally compensated NTD natGe:Ga,As samples with K = 0.32. For the case of the uncompensated series in zero magnetic field, the critical exponents μ, ν, and ζ determined for the electrical conductivity (σ), localization length (ξ), and impurity dielectric susceptability (χimp), respectively, change at the very vicinity of the critical Ga concentration (N ∼ Nc). Namely, the anomalous critical exponents, e.g. μ ≈ 0.5, change to μ ≈ 1 only within the region 0.99Nc < N < 1.01Nc. On the other hand, the same critical behavior, μ ≈ 1, was found for the K = 0.32 series in much larger region 0.25Nc < N < 2ANc. This finding suggests that the μ ≈ 1 critical behavior observed for the nominally uncompensated series in the extremely narrow region is due to the presence of the self-compensation of acceptors by native defects and/or technologically unavoidable very small amount of doping compensation (K < 0.001). Therefore, the width of the concentration that can be fitted with μ ≈ 1 around N c is likely to scale with the degree of compensation (K), and disappears in the limit K → 0, i.e., only the region with the anomalous exponent μ ≈ 0.5 remains for the case of K = 0. An externally applied magnetic field to nominally uncompensated samples also broadens the width of μ ≈ 1 around Nc, but with a mechanism clearly different from that of compensation. The unified description of our experimental results unambiguously establishes the values of the critical exponents μ, ν, and ζ for doped semiconductors with and without compensation and magnetic field.

Original languageEnglish
Pages (from-to)173-183
Number of pages11
JournalJournal of the Physical Society of Japan
Volume73
Issue number1
DOIs
Publication statusPublished - 2004 Jan

Fingerprint

insulators
scaling
magnetic fields
exponents
metals
nuclear reactions
transport properties
impurities
electrical resistivity
defects
electrons

Keywords

  • Doped semiconductor
  • Hopping conduction
  • Metal-insulator transition
  • Mott-Anderson transition
  • Scaling theory

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Complete scaling analysis of the metal-insulator transition in Ge : Ga: Effects of doping-compensation and magnetic field. / Itoh, Kohei M; Watanabe, Michio; Ootuka, Youiti; Haller, Eugene E.; Ohtsuki, Tomi.

In: Journal of the Physical Society of Japan, Vol. 73, No. 1, 01.2004, p. 173-183.

Research output: Contribution to journalArticle

Itoh, Kohei M ; Watanabe, Michio ; Ootuka, Youiti ; Haller, Eugene E. ; Ohtsuki, Tomi. / Complete scaling analysis of the metal-insulator transition in Ge : Ga: Effects of doping-compensation and magnetic field. In: Journal of the Physical Society of Japan. 2004 ; Vol. 73, No. 1. pp. 173-183.
@article{82350dd88b364a8ab40af4f5b791bf82,
title = "Complete scaling analysis of the metal-insulator transition in Ge: Ga: Effects of doping-compensation and magnetic field",
abstract = "We report on the complete scaling analysis of low temperature electron transport properties with and without magnetic field in the critical regime for the metal-insulator transition in two series of homogeneously doped p-type Ge samples: i) nominally uncompensated neutron-transmutation-doped (NTD) 70Ge:Ga samples with the technological compensation ratio K < 0.001, and ii) intentionally compensated NTD natGe:Ga,As samples with K = 0.32. For the case of the uncompensated series in zero magnetic field, the critical exponents μ, ν, and ζ determined for the electrical conductivity (σ), localization length (ξ), and impurity dielectric susceptability (χimp), respectively, change at the very vicinity of the critical Ga concentration (N ∼ Nc). Namely, the anomalous critical exponents, e.g. μ ≈ 0.5, change to μ ≈ 1 only within the region 0.99Nc < N < 1.01Nc. On the other hand, the same critical behavior, μ ≈ 1, was found for the K = 0.32 series in much larger region 0.25Nc < N < 2ANc. This finding suggests that the μ ≈ 1 critical behavior observed for the nominally uncompensated series in the extremely narrow region is due to the presence of the self-compensation of acceptors by native defects and/or technologically unavoidable very small amount of doping compensation (K < 0.001). Therefore, the width of the concentration that can be fitted with μ ≈ 1 around N c is likely to scale with the degree of compensation (K), and disappears in the limit K → 0, i.e., only the region with the anomalous exponent μ ≈ 0.5 remains for the case of K = 0. An externally applied magnetic field to nominally uncompensated samples also broadens the width of μ ≈ 1 around Nc, but with a mechanism clearly different from that of compensation. The unified description of our experimental results unambiguously establishes the values of the critical exponents μ, ν, and ζ for doped semiconductors with and without compensation and magnetic field.",
keywords = "Doped semiconductor, Hopping conduction, Metal-insulator transition, Mott-Anderson transition, Scaling theory",
author = "Itoh, {Kohei M} and Michio Watanabe and Youiti Ootuka and Haller, {Eugene E.} and Tomi Ohtsuki",
year = "2004",
month = "1",
doi = "10.1143/JPSJ.73.173",
language = "English",
volume = "73",
pages = "173--183",
journal = "Journal of the Physical Society of Japan",
issn = "0031-9015",
publisher = "Physical Society of Japan",
number = "1",

}

TY - JOUR

T1 - Complete scaling analysis of the metal-insulator transition in Ge

T2 - Ga: Effects of doping-compensation and magnetic field

AU - Itoh, Kohei M

AU - Watanabe, Michio

AU - Ootuka, Youiti

AU - Haller, Eugene E.

AU - Ohtsuki, Tomi

PY - 2004/1

Y1 - 2004/1

N2 - We report on the complete scaling analysis of low temperature electron transport properties with and without magnetic field in the critical regime for the metal-insulator transition in two series of homogeneously doped p-type Ge samples: i) nominally uncompensated neutron-transmutation-doped (NTD) 70Ge:Ga samples with the technological compensation ratio K < 0.001, and ii) intentionally compensated NTD natGe:Ga,As samples with K = 0.32. For the case of the uncompensated series in zero magnetic field, the critical exponents μ, ν, and ζ determined for the electrical conductivity (σ), localization length (ξ), and impurity dielectric susceptability (χimp), respectively, change at the very vicinity of the critical Ga concentration (N ∼ Nc). Namely, the anomalous critical exponents, e.g. μ ≈ 0.5, change to μ ≈ 1 only within the region 0.99Nc < N < 1.01Nc. On the other hand, the same critical behavior, μ ≈ 1, was found for the K = 0.32 series in much larger region 0.25Nc < N < 2ANc. This finding suggests that the μ ≈ 1 critical behavior observed for the nominally uncompensated series in the extremely narrow region is due to the presence of the self-compensation of acceptors by native defects and/or technologically unavoidable very small amount of doping compensation (K < 0.001). Therefore, the width of the concentration that can be fitted with μ ≈ 1 around N c is likely to scale with the degree of compensation (K), and disappears in the limit K → 0, i.e., only the region with the anomalous exponent μ ≈ 0.5 remains for the case of K = 0. An externally applied magnetic field to nominally uncompensated samples also broadens the width of μ ≈ 1 around Nc, but with a mechanism clearly different from that of compensation. The unified description of our experimental results unambiguously establishes the values of the critical exponents μ, ν, and ζ for doped semiconductors with and without compensation and magnetic field.

AB - We report on the complete scaling analysis of low temperature electron transport properties with and without magnetic field in the critical regime for the metal-insulator transition in two series of homogeneously doped p-type Ge samples: i) nominally uncompensated neutron-transmutation-doped (NTD) 70Ge:Ga samples with the technological compensation ratio K < 0.001, and ii) intentionally compensated NTD natGe:Ga,As samples with K = 0.32. For the case of the uncompensated series in zero magnetic field, the critical exponents μ, ν, and ζ determined for the electrical conductivity (σ), localization length (ξ), and impurity dielectric susceptability (χimp), respectively, change at the very vicinity of the critical Ga concentration (N ∼ Nc). Namely, the anomalous critical exponents, e.g. μ ≈ 0.5, change to μ ≈ 1 only within the region 0.99Nc < N < 1.01Nc. On the other hand, the same critical behavior, μ ≈ 1, was found for the K = 0.32 series in much larger region 0.25Nc < N < 2ANc. This finding suggests that the μ ≈ 1 critical behavior observed for the nominally uncompensated series in the extremely narrow region is due to the presence of the self-compensation of acceptors by native defects and/or technologically unavoidable very small amount of doping compensation (K < 0.001). Therefore, the width of the concentration that can be fitted with μ ≈ 1 around N c is likely to scale with the degree of compensation (K), and disappears in the limit K → 0, i.e., only the region with the anomalous exponent μ ≈ 0.5 remains for the case of K = 0. An externally applied magnetic field to nominally uncompensated samples also broadens the width of μ ≈ 1 around Nc, but with a mechanism clearly different from that of compensation. The unified description of our experimental results unambiguously establishes the values of the critical exponents μ, ν, and ζ for doped semiconductors with and without compensation and magnetic field.

KW - Doped semiconductor

KW - Hopping conduction

KW - Metal-insulator transition

KW - Mott-Anderson transition

KW - Scaling theory

UR - http://www.scopus.com/inward/record.url?scp=21144457622&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=21144457622&partnerID=8YFLogxK

U2 - 10.1143/JPSJ.73.173

DO - 10.1143/JPSJ.73.173

M3 - Article

AN - SCOPUS:21144457622

VL - 73

SP - 173

EP - 183

JO - Journal of the Physical Society of Japan

JF - Journal of the Physical Society of Japan

SN - 0031-9015

IS - 1

ER -