Metal-insulator transition in heavily doped semiconductors

Löhneysen, H. v.

doi:10.1016/s1359-0286(98)80059-4

Cited by 13 publications

(14 citation statements)

References 87 publications

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“…(iv) Can this model be extended to the description of other quantities such as the magnetoresistance? (v) Last, but not least, it should be noted that the conclusions drawn above are very different from the description of heavily doped crystalline semiconductors given in a previous review in this journal, i.e., in [19]. On the other hand, Fig.…”

Section: Discussionmentioning

confidence: 55%

“…Milestones were the concepts of Anderson localisation [1], variable-range hopping [2], minimum metallic conductivity [3], the Coulomb glass [4,5], the scaling theory of localisation of noninteracting electrons [6], and the renormalisation group approach incorporating the electron-electron interaction into localisation theory [7,8]. In the literature, many surveys have appeared in this wide area [9][10][11][12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Metal–insulator transition in amorphous alloys

Möbius

1999

Current Opinion in Solid State and Materials Science

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We focus on the central problem of discriminating between metallic and insulating behaviour in amorphous alloys formed between a semiconductor and a metal. For this, the logarithmic temperature derivative of the conductivity, w = d ln σ/d ln T , has proved over recent years to be very helpful in determining the critical value x c of the metal content x for the metal-insulator transition (MIT). We show that, for various amorphous alloys, recent experimental results on w(T, x) are qualitatively inconsistent with the usual assumptions of continuity of the MIT at T = 0 and of σ(T, x c ) being proportional to a power of T . These results suggest that w(T, x c ) tends to 0 as T → 0, in which case the MIT should be discontinuous at T = 0 (but only there), in agreement with Mott's hypothesis of a finite minimum metallic conductivity. 71.30.+h,71.23.Cq, Typeset using REVT E X Abbreviations EDX: energy dispersive X-ray analysis MIT: metal-insulator transition MOSFET: metal oxide semiconductor field effect transistor RBS: Rutherford backscattering analysis

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Section: Discussionmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Metal–insulator transition in amorphous alloys

Möbius

1999

Current Opinion in Solid State and Materials Science

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“…In the case of the n-doped semiconductors, the MIT appears at a doping density n c where the Fermi level is in the impurity band [28][29][30] . Electron-electron interactions are crucial in order to account for the observed features of the MIT [11][12][13] and induce significant many-body effects on the insulating side of the transition (n i < n c ). Therefore, we restrict our work to metallic densities (n i > n c ) away from the critical region, where a single-particle description is possible.…”

Section: Introductionmentioning

confidence: 99%

Charge and spin diffusion on the metallic side of the metal-insulator transition: A self-consistent approach

Wellens

Jalabert

2016

Phys. Rev. B

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We develop a self-consistent theory describing the spin and spatial electron diffusion in the impurity band of doped semiconductors under the effect of a weak spin-orbit coupling. The resulting low-temperature spinrelaxation time and diffusion coefficient are calculated within different schemes of the self-consistent framework. The simplest of these schemes qualitatively reproduces previous phenomenological developments, while more elaborate calculations provide corrections that approach the values obtained in numerical simulations. The results are universal for zinc-blende semiconductors with electron conductance in the impurity band, and thus they are able to account for the measured spin-relaxation times of materials with very different physical parameters. From a general point of view, our theory opens a new perspective for describing the hopping dynamics in random quantum networks.

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“…15 Experimentally, localization in three-dimensional systems has been studied in a large number of disordered solids, such as heavily doped crystalline semiconductors (in which the disorder arises from the randomly positioned impurities), amorphous transition-metal semiconductor alloys, granular metals, and nanocrystalline substances. [7][8][9][10] Many of these solids are or may become application relevant; therefore they are often considered to be among the materials. 3 In various experiments, the MIT has been triggered by diverse control parameters: composition / doping, stress, magnetic field, light, as well as structure; [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] in part, these publications substantially contradict each other.…”

Section: Introductionmentioning

confidence: 99%

The metal-insulator transition in disordered solids: How theoretical prejudices influence its characterization A critical review of analyses of experimental data

Möbius

2018

Critical Reviews in Solid State and Materials Sciences

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In a recent experimental study, Siegrist et al. [Nature Materials 10, 202-208 (2011)] investigated the metal-insulator transition (MIT) induced by annealing in GeSb 2 Te 4 . The authors concluded that this phase-change material exhibits a discontinuous MIT with finite minimum metallic conductivity. The striking contrast between their work and reports on many other disordered substances from the last decades motivates the present in-depth study of the influence of the MIT criterion used on the character of the MIT derived.First, we discuss in detail the inherent biases of various approaches to locating the MIT. Second, reanalyzing GeSb 2 Te 4 data, we show that this material resembles other disordered solids to a large extent: according to a widely-used approach, its temperature dependences of the conductivity, s(T ), may likewise be interpreted in terms of a continuous MIT. Third, examining previous experimental studies of crystalline Si:As, Si:P, Si:B, Ge:Ga, CdSe:In, n-Cd 0:95 Mn 0:05 Se, Cd 0:95 Mn 0:05 Te 0:97 Se 0:03 :In, disordered Gd, and nanogranular Pt-C, we detect substantial problems in the interpretations of s(T ) in numerous studies which claim the MIT to be continuous: Evaluating the logarithmic derivative d ln s/d ln T highlights serious inconsistencies. In part, they are common to all such studies and seem to be generic, in part, they vary from experiment to experiment. Fourth, for four qualitatively different phenomenological models of the temperature and control parameter dependence of the conductivity, we present the respective flow diagrams of d ln s/d ln T. In consequence, the likely generic inconsistencies seem to originate from the MIT being discontinuous, in contradiction to most of the original interpretations.Because of the large number and diversity of the experiments considered, these inconsistencies provide overwhelming evidence against the common, localization theory motivated interpretations. The primary challenges now lie in improving measurement precision and accuracy, rather than in extending the temperature range, and in developing a microscopic theory which explains the seemingly generic features of d ln s/d ln T.

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Metal-insulator transition in heavily doped semiconductors

Cited by 13 publications

References 87 publications

Metal–insulator transition in amorphous alloys

Metal–insulator transition in amorphous alloys

Charge and spin diffusion on the metallic side of the metal-insulator transition: A self-consistent approach

The metal-insulator transition in disordered solids: How theoretical prejudices influence its characterization A critical review of analyses of experimental data

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