scholarly journals Metallicity and Superconductivity in Doped Strontium Titanate

2019 ◽  
Vol 10 (1) ◽  
pp. 25-44 ◽  
Author(s):  
Clément Collignon ◽  
Xiao Lin ◽  
Carl Willem Rischau ◽  
Benoît Fauqué ◽  
Kamran Behnia
Keyword(s):  
Liquid Helium ◽  
Free Path ◽  
Coulomb Interaction ◽  
Strontium Titanate ◽  
Room Temperature ◽  
Mean Free Path ◽  
Helium Temperature ◽  
Ongoing Research ◽  
Low Concentrations ◽  
Wide Gap

Strontium titanate is a wide-gap semiconductor avoiding a ferroelectric instability thanks to quantum fluctuations. This proximity leads to strong screening of static Coulomb interaction and paves the way for the emergence of a very dilute metal with extremely mobile carriers at liquid-helium temperature. Upon warming, mobility decreases by several orders of magnitude. Yet, metallicity persists above room temperature even when the apparent mean free path falls below the electron wavelength. The superconducting instability survives at exceptionally low concentrations and beyond the boundaries of Migdal–Eliashberg approximation. An intimate connection between dilute superconductivity and aborted ferroelectricity is widely suspected. In this review, we give a brief account of ongoing research on bulk strontium titanate as an insulator, a metal, and a superconductor.

Experiments on the flow of heat in liquid helium below 0.7 °K

1958 ◽  
Vol 246 (1246) ◽  
pp. 390-405 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Liquid Helium ◽  
Free Path ◽  
Empirical Relation ◽  
Mean Free Path ◽  
Series Of Experiments ◽  
The Mean ◽  
Set Up ◽  
Low Pressures ◽  
Measured Thermal Conductivity

A series of experiments has been performed to study the steady flow of heat in liquid helium in tubes of diameter 0.05 to 1.0 cm at temperatures between 0.25 and 0.7 °K. The results are interpreted in terms of the flow of a gas of phonons, in which the mean free path λ varies with temperature, and may be either greater or less than the diameter of the tube d . When λ ≫ d the flow is limited by the scattering of the phonons at the walls, and the effect of the surface has been studied, but when λ ≪ d viscous flow is set up in which the measured thermal conductivity is increased above that for wall scattering. This behaviour is very similar to that observed in the flow of gases at low pressures, and by applying kinetic theory to the problem it can be shown that the mean free path of the phonons characterizing viscosity can be expressed by the empirical relation λ = 3.8 x 10 -3 T -4.3 cm. This result is inconsistent with the temperature dependence of λ as T -9 predicted theoretically by Landau & Khalatnikov (1949).

The mean free path of mobile dislocations in doped NaCl single crystals measured by N.M.R. between room temperature and 300°C

1982 ◽  
Vol 46 (3) ◽  
pp. 469-481 ◽  
Author(s):  
W. H. M. Alsem ◽  
J. Th. M. De Hosson ◽  
R. Muenter ◽  
H. Tamler ◽  
O. Kanert
Keyword(s):  
Single Crystals ◽  
Free Path ◽  
Room Temperature ◽  
Mean Free Path ◽  
The Mean

scholarly journals Low-Temperature Properties of the Magnetic Sensor with Amorphous Wire

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6986
Author(s):  
Dongfeng He ◽  
Kensei Umemori ◽  
Ryuichi Ueki ◽  
Takeshi Dohmae ◽  
Takafumi Okada ◽  
...  
Keyword(s):  
Low Temperature ◽  
Liquid Helium ◽  
Room Temperature ◽  
Magnetic Sensor ◽  
Liquid Helium Temperature ◽  
Coaxial Cable ◽  
Amorphous Wire ◽  
Helium Temperature ◽  
Sensing Element ◽  
The One

We found that a magnetic sensor made of a coil wound around a 5 f0.1 mm (Fe0.06Co0.94)72.5Si2.5B15 (FeCoSiB) amorphous wire could operate in a wide temperature range from room temperature to liquid helium temperature (4.2 K). The low-temperature sensing element of the sensor was connected to the room-temperature driving circuit by only one coaxial cable with a diameter of 1 mm. The one-cable design of the magnetic sensor reduced the heat transferring through the cable to the liquid helium. To develop a magnetic sensing system capable of operating at liquid helium temperature, we evaluated the low-temperature properties of the FeCoSiB magnetic sensor.

Heat flow in liquid helium in the transition region

1970 ◽  
Vol 315 (1521) ◽  
pp. 239-247 ◽  
Keyword(s):  
Heat Flow ◽  
Liquid Helium ◽  
Free Path ◽  
Transition Region ◽  
Cross Section ◽  
Low Temperatures ◽  
Circular Cross Section ◽  
Mean Free Path ◽  
Theoretical Treatment ◽  
Tube Radius

A theoretical treatment is given of heat flow at low temperatures in liquid helium, contained in a tube of circular cross-section. Results are obtained for arbitrary ratio of phonon–phonon collision mean free path to tube radius, and agree with experiment to within a few parts per cent.

scholarly journals Heat transport by long mean free path vibrations in amorphous silicon nitride near room temperature

2013 ◽  
Vol 87 (21) ◽  
Author(s):  
Rubina Sultan ◽  
A. D. Avery ◽  
J. M. Underwood ◽  
S. J. Mason ◽  
D. Bassett ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Heat Transport ◽  
Free Path ◽  
Room Temperature ◽  
Mean Free Path ◽  
Amorphous Silicon Nitride

scholarly journals Reduction of phonon mean free path: From low-temperature physics to room temperature applications in thermoelectricity

2016 ◽  
Vol 17 (10) ◽  
pp. 1154-1160 ◽  
Author(s):  
Olivier Bourgeois ◽  
Dimitri Tainoff ◽  
Adib Tavakoli ◽  
Yanqing Liu ◽  
Christophe Blanc ◽  
...  
Keyword(s):  
Low Temperature ◽  
Free Path ◽  
Room Temperature ◽  
Mean Free Path ◽  
Low Temperature Physics ◽  
Temperature Applications

Thickness-dependent in-plane thermal conductivity of suspended MoS2 grown by chemical vapor deposition

Nanoscale ◽  
2017 ◽  
Vol 9 (7) ◽  
pp. 2541-2547 ◽  
Author(s):  
Jung Jun Bae ◽  
Hye Yun Jeong ◽  
Gang Hee Han ◽  
Jaesu Kim ◽  
Hyun Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Chemical Vapor Deposition ◽  
Free Path ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Mean Free Path

We observe that the Fuchs–Sondheimer model works for the thickness-dependent thermal conductivity of MoS2 down to 10 nm in thickness at room temperature, yielding a phonon mean free path of 17 nm for bulk.

Radiation-Induced Movement of a Mercury Stain at Room Temperature and Liquid Helium Temperature

1982 ◽  
Vol 40 ◽  
pp. 376-377
Author(s):  
M. K. Lamvik ◽  
K. -H. Müller ◽  
K. Weiss
Keyword(s):  
Electron Microscope ◽  
Radiation Damage ◽  
Liquid Helium ◽  
Heavy Element ◽  
Room Temperature ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Radiation Induced ◽  
Preliminary Study ◽  
Effects Of Radiation

Cryomicroscopy at liquid helium temperature has shown promise in protecting organic materials from the effects of radiation damage, and it might be expected that sensitive heavy-element stains would be similarly protected. We have made a preliminary study of a positively-stained protein specimen using the superconducting-objective electron microscope at Berlin. We have used the mercury stain TAMM, solubilized with penicillamine (TAMM-pen3), which is known to be radiation-sensitive, on tropomyosin paracrystals of the type made by Ohtsuki. Specimens were treated with 10μM TAMM-pen3 on the grid for times ranging from 15 min to 11 hr, then were washed with 1 ml water, blotted and dried. Staining time had little effect on our results. Here we are not studying the protein or stain specificity; our interest is in the movement of the stain, which we can clearly demonstrate.

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