M. du Bois-Reymond goes to Paris

Finkelstein, Gabriel

doi:10.1017/s0007087403005065

Cited by 17 publications

(17 citation statements)

References 2 publications

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“…Potentially, strong interactions might drive an electron system towards ferromagnetic instability [4]. Moreover, it has been suggested that the 'metallic' behavior in 2D is accompanied by a tendency to a ferromagnetic instability [12]. Thus, in relation to the still open question of the origin of the 2D MIT, direct measurements of these quantities in the dilute regime near the 2D MIT are crucial.…”

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confidence: 99%

Low-Density Spin Susceptibility and Effective Mass of Mobile Electrons in Si Inversion Layers

et al. 2002

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We studied the Shubnikov-de Haas (SdH) oscillations in high-mobility Si-MOS samples over a wide range of carrier densities n ≃ (1 − 50) × 10 11 cm −2 , which includes the vicinity of the apparent metal-insulator transition in two dimensions (2D MIT). Using a novel technique of measuring the SdH oscillations in superimposed and independently controlled parallel and perpendicular magnetic fields, we determined the spin susceptibility χ * , the effective mass m * , and the g * -factor for mobile electrons. These quantities increase gradually with decreasing density; near the 2D MIT, we observed enhancement of χ * by a factor of ∼ 4.7.71. 30.+h, 73.40.Qv, 71.27.+a Many two-dimensional (2D) systems exhibit an apparent metal-insulator transition (MIT) at low temperatures as the electron density n is decreased below a critical density n c (for reviews see, e.g., Refs. [1][2][3]). The phenomena of the MIT and 'metallic' conductivity in 2D attract a great deal of interest, because it addresses a fundamental problem of the ground state of strongly correlated electron systems. The strength of electron-electron interactions is characterized by the ratio r s of the Coulomb interaction energy to the Fermi energy ǫ F . The 2D MIT is observed in Si MOSFETs at n c ∼ 1 × 10 11 cm −2 , which corresponds to r s ∼ 8 (for 2D electrons in (100)-Si, r s = 2.63 10 12 cm −2 /n).In the theory of electron liquid, the electron effective mass m * , the g * -factor, and the spin susceptibility χ * ∝ g * m * are renormalized depending on r s [4]. Though the quantitative theoretical results [5][6][7] vary considerably, all of them suggest enhancement of χ * , m * and g * with r s . Earlier experiments [8][9][10][11] have shown growth of m * and g * m * at relatively small r s values, pointing to a ferromagnetic type of interactions in the explored range 1 < ∼ r s < 6.5. Potentially, strong interactions might drive an electron system towards ferromagnetic instability [4]. Moreover, it has been suggested that the 'metallic' behavior in 2D is accompanied by a tendency to a ferromagnetic instability [12]. Thus, in relation to the still open question of the origin of the 2D MIT, direct measurements of these quantities in the dilute regime near the 2D MIT are crucial.In this Letter, we report the direct measurements of χ * , m * , and hence g * over a wide range of carrier densities (1 ≤ r s ≤ 8.4), which extends for the first time down to and across the 2D MIT. The data were obtained by a novel technique of measuring the interference pattern of Shubnikov-de Haas (SdH) oscillations in crossed magnetic fields. The conventional technique of measuring g * m * in tilted magnetic fields [8,10] is not applicable when the Zeeman energy is greater than the cyclotron energy [13]. The crossed field technique removes this restriction and allows us to extend measurements over the wider range of r s . We find that for small r s , the g * m *values increase slowly in agreement with the earlier data by Fang and Stiles [8] and Okamoto et al. [10]. For larger valu...

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confidence: 99%

Low-Density Spin Susceptibility and Effective Mass of Mobile Electrons in Si Inversion Layers

et al. 2002

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“…Like the Academy of Sciences, the Academy of Medicine served as a jury of peers (functioning through appointed committees) to judge medical/ surgical innovations of both a theoretical and practical nature. For example, in a recent article we learn that du Bois-Reymond traveled from Berlin to Paris in 1849 to present his physiological research to the Academy of Sciences (Finkelstein 2003). And Weisz has described how new surgical/therapeutic procedures were demonstrated at the Academy of Medicine for approval from its members (Weisz 1995).…”

Section: The Nature and Purpose Of Academic Debatementioning

confidence: 99%

“…Paris was undisputed as the European center of science and medicine up to the mid-1830s, but for many scientists, such as the German physiologist Emil du-Bois-Reymond, Paris still held this position at mid-century (Finkelstein 2003). No other city, no other academies besides the Paris Academy of Medicine and the Paris Academy of Sciences could claim as much.…”

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Debate as Scientific Practice in Nineteenth-Century Paris: The Controversy Over the Microscope

Berge¹

2004

Perspectives on Science

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This article explores debate as a key scientiªc practice among the medical elite in nineteenth-century Paris, with an emphasis on academic debate and debate in the scientiªc/medical press. I use the debate over the microscope, which took place in the Paris Academy of Medicine in 1854-55 and concurrently in the medical press, to illustrate the role of debate as scientiªc practice. Focusing on the debate in the press, I show how medical journalists used the debate in the Academy to raise larger questions about the nature of science and medicine and to legitimate French microscopy. I suggest that debate was an important scientiªc practice in nineteenth-century Paris, not only owing to a longstanding belief that truth emerges through disputation but also depending on and exemplifying a shared masculine culture of honor.

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“…Properly quantified (and quantized) action potentials are, in the practices I describe, cor-3. What are now called "action potentials" were first called "negative oscillations" ("negative Schwankung") in 1872 by Emil du Bois-Reymond (see Finkelstein 2003). Julius Bernstein, a student of du Bois-Reymond (as well as of Helmholtz), in 1902 proposed an early theory of how these pulses worked (Schuetze 1983).…”

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confidence: 99%