#conductivity

[ulises-aithon]

It is so funny how utterly unintelligible can an Excel be. Do not speak the old magic to me, spreadsheets for I was there when you were written. He's under the horrors:

I was able to help it a little but oh my, the work's truly endless. When I finish this I have to go to the next question, not next project but question.

It's awful in here

[materialsscienceandengineering]

Carbon nanotubes are closing the gap on copper conductivity

Carbon nanotubes are one technology that many observers believe hasn't quite lived up to the extreme hype that surrounded them when they first appeared on the scene in the late 1990s. At that time, much was made of their extraordinary electrical, thermal, and mechanical properties, with predictions that they would revolutionize materials science, electronics, and daily life. But could we be closer to realizing some of that promise? In a paper published in the journal Science, researchers describe a method for adding a chemical to carbon nanotube bundles that brings them closer to copper's ability to conduct electricity.

Read more.

[wayti-blog]

"A flower-like pattern exposes chiral superconductivity's long-sought fingerprint"

"Scientists have known about superconductivity for more than a century. At low temperatures, resistance in certain materials vanishes and they carry electrical current without losing any energy. Superconductors are part of particle accelerators and magnetic resonance imaging machines. While they need extremely cool environments to work, the mechanism that drives them is quite well understood: electrons, which normally repel each other, form pairs and carry the current.

("The center of each image (a) and (b) shows a substitutional silicon defect. The pronounced dark spot at the center of panels (a) and (c), indicated by blue arrows, is a key signature of a chiral superconducting order parameter. The top two panels are experimental data; the lower two panels are theoretical simulations. Credit: Physical Review X (2026). DOI: 10.1103/jmmf-mpr8")

Chiral superconductivity is another story. Here, electron pairs reject the typical symmetry and twist into a signature left or right "handedness." Scientists have searched for this phase for decades because it has promise for quantum technologies.

In 2023, Chancellor's Professor Hanno Weitering and Bains Professor Steve Johnston published findings in Nature Physics reporting that strategically scattering tin atoms across a silicon base could give rise to a superconductor. They proposed the system could also be a potential chiral superconductor. This latest work, outlined in Physical Review X, provides the evidence."

("Fourier transformed QPI images for bias voltages of (a) −1.3, (b) −0.8, (c) −0.5, (d) +1.3, (e) +0.8, and (f) +0.5 meV, as indicated in each panel. These images correspond to the dI/dV maps in Fig. 2. The 2kF wave vector and G11 reciprocal lattice vector are indicated in panel (c). ΓK¯ is shown in panel (f). For a detailed explanation of these momentum space images, (...) Credit: Physical Review X (2026)")

"Weitering said the structural and electronic simplicity of the tin-silicon material is the key to seeing chirality. More complex materials have overlapping states and multiple interactions that can mask the telltale patterns.

In this system, one-third layer of tin means a controlled deposition of atoms placed relatively far apart on a silicon layer. Those atoms spontaneously organize into a nicely ordered triangular lattice. The geometry is important."

"To see chiral superconductivity's distinctive fingerprint, he and his colleagues turned to quasiparticle interference imaging, or QPI.

"In condensed matter, these particles are always moving in a surrounding that affects their behavior, so they're not really a single entity anymore," Weitering said. "They're all under the influence of their surroundings. That's why we call them quasiparticles."

If you picture electrons behaving like waves, he explained, and think about throwing stones in a pond, one after another in different spots, you'll see waves start to run into each other.

"We call those interference patterns," he said. "This is where the interference comes from: quasiparticle interference. With the scanning tunneling microscope (STM) we can see those waves. Quasiparticles interfere and give these beautiful patterns.""

continue reading article

[tine5]

Graphite acting as a conductive material

[stone-cold-groove]

Rare earths for better magnets. Ad for Bell Laboratories - 1970.

[mineralsrocksandfossiltalks]

Wordplay Wednesday: Conductivity

Conductivity refers to a material's ability to allow electricity or heat to flow through it. Metals tend to be very good conductors. This has to do with the outer shell of electrons and their ability to freely dissociate from the rest of the atom.

Notice that each of these metals have less than 4 valence electrons (electrons in the outer most shell or ring on the diagrams). All of these can easily move and transport an electrical or thermal current.

Silicon and carbon have four valence electrons making them semiconductors. Their valence electrons are a little more tightly bound to the atom making it harder for them to move. Modifications to semiconductor crystal structures can allow them to conduct better.

Elements like oxygen and phosphorous have more than four valence electrons. This binds them tightly to the atom and does allow freedom of movement. We call these insulators.

To get an electrical current, electrons need somewhere to move. Many simple experiments use copper and zinc because they are neighbors on the periodic table with copper being slightly more electronegative than zinc (it really wants zinc's electrons). Electrons flow from negative to positive while the electrical current flows from positive to negative.

Things change about for nonmetals when it comes to heat conduction because it has less to do with valence electrons and more to do with the vibrations of the atomic lattice. This typically means that they conduct better at higher temperatures (unless they are high-quality crystal). Diamonds are some of the best thermal conductors out there because of their highly ordered crystal structure. However, it is an electrical insulator.

Heat moves in one of three ways: conduction, convection, or radiation. Conduction is the transfer of heat from a warmer material to a cooler one.

Convection is the movement of heat through a fluid (liquid or gas).

Radiation is heat energy transferred through electromagnetic waves.

That's all for now on conductivity. Tomorrow starts our new topic: Igneous Rocks. Tune in to learn about a famous igneous petrologist who revolutionized the study of igneous rocks. Fossilize you later!

[tcipkpl]

The world I live without you.

sanderick