Science

1283 Articles

Fastest Semiconductor May Also Be Most Expensive

November 9, 2023 by 26 Comments

Scientists have found what they think may be the fastest known semiconductor. Sounds great, right? But it happens to made from one of the rarest elements: rhenium. That rare element combines with selenium and chlorine to form a “superatom.” Unlike conventional semiconductor material, the superatom causes phonons to bind together and resist scattering. This should allow materials that can process signals in femtoseconds,

Rhenium was the last stable element to be found in 1925. It is primarily used in combination with nickel in parts of jet engines, although it is also known as a catalyst for certain reactions. It is very rare and has a high melting point, exceeded only by tungsten and carbon. When it was discovered, scientists extracted a single gram of the material by processing 660 kg of molybdenite. Because of its rarity, it is expensive, costing anywhere from $2,800 to $10,600 per kilogram.

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All About Cats, And What Ethernet Classifications Mean Beyond ‘Bigger Number Better’

November 7, 2023 by 48 Comments

Although it probably feels like forever to many of us since Category 5 Ethernet cabling became prevalent, now that 2.5 and even 5 Gbit Ethernet has trickled into the mainstream, a pertinent question that many probably end up asking, is when you should replace Cat-5e wiring with Cat-6, or even Cat-7. Since most of us are likely to use copper network wiring for the foreseeable future in our domiciles and offices, it is a good question that deserves a good answer. Although swapping a Cat-5e patch cable with a Cat-7 one between a network port and computer is easy enough, replacing all the network cable already pulled through the conduits of a ‘future-proofed’ home is not.

The good news is probably that Category 8 Class II (Cat-8.2) is all you need to run your 40 Gbit Ethernet network with standard twisted pair wiring. The bad news is that you’re limited to runs of only thirty meters before signal degradation begins to kick in. If you take things down a notch to Cat-6A or Cat-7 (ISO/IEC 11801 Class EA and F, respectively), you can do 100 meter runs at 10 Gbit/s just like 100 meters runs at 1 Gbit/s were possible with Cat-5e before. Yet what differentiates these categories exactly?

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A schematic representation of the different ionospheric sub-layers and how they evolve daily from day to night periods. (Credit: Carlos Molina)

Ham Radio Operators’ Ionospheric Science During The Solar Eclipse

October 31, 2023 by 3 Comments

The Earth’s ionosphere is the ionized upper part of the atmosphere, and it’s also the most dynamic as it swells and ebbs depending on whether it’s exposed to the Sun or not. It’s the ionosphere that enables radio frequency communications to reach beyond the horizon, its thickness and composition also affects the range and quality of these transmissions. Using this knowledge, a group of ham radio operators used the October 14 solar eclipse to crowdsource an experiment, as part of the Ham Science Citizen Investigation (HamSCI) community.

A solar eclipse is an interesting consideration with ionospheric RF transmissions, as it essentially creates a temporary period of night time, which is when the ionosphere is the least dense, and thus weakening these transmissions and their total range. As with previous solar eclipses, they turned it into a kind of game, where each ham operator attempts to contact as many others as possible within the least amount of time. Using the collected data points on who was able to talk to whom on the globe, the event’s effect on RF transmissions could be plotted over time. For the August 21, 2017 solar eclipse, the results were published in a 2018 paper by N. A. Frissell et al. in Geophysical Research Letters.

One point which they wished to examine during the 2023 solar eclipse were the plasma bubbles that form near the Earth’s magnetic equator, in regions like Brazil. These plasma bubbles cause a lot of interference, which in the preliminary data can be seen as a clear Doppler shift of the signal due to the diffusion of the ionosphere as the eclipse’s effect took hold. For the next solar eclipse in April 2024 another experiment is scheduled, which will give even more ham radio operators the chance to sign up and contribute to ionospheric science.

Top image: A schematic representation of the different ionospheric sub-layers and how they evolve daily from day to night periods. (Credit: Carlos Molina)

Particle Accelerator… On A Chip

October 30, 2023 by 21 Comments

When you think of a particle accelerator, you usually think of some giant cyclotron with heavy-duty equipment in a massive mad-science lab. But scientists now believe they can create particle accelerators that can fit on a chip smaller than a penny. The device uses lasers and dielectrics instead of electric fields and metal. The conventional accelerators are limited by the peak fields the metallic surfaces can withstand. Dielectric materials can withstand much higher fields but, of course, don’t conduct electricity.

Physicists fabricated a 225 nanometers wide channel in various sizes up to 0.5 millimeters long. An electron beam moves through the channel. Very short infrared laser pulses on top of the channels accelerate the electrons down it using tiny silicon pillars.

The electron beam entered the channel at 28,400 electron volts. They exited at 40,700 electron volts, a substantial increase. The tiny pillars are only two microns high, so fabrication is tricky. Possible applications include cancer treatment, electron microscopy, and the creation of compact high-energy lasers.

The nanofabrication required for these devices won’t be in our garage any time soon. However, we hope this might lead to a new class of devices that we can use to build exciting new things. After all, remember how it used to be hard to build things using a laser?

We’ve seen laser-based accelerators before. If you want a history of particle accelerators, we can help you there, too.

The Simulated Universe Thought Experiment And Information Entropy

October 26, 2023 by 38 Comments

Do we live in a simulation? This is one of those questions which has kept at least part of humanity awake at night, and which has led to a number of successful books and movies being made on the subject, topped perhaps by the blockbuster  movie The Matrix. Yet the traditional interpretation of the ‘simulated universe’ thought experiment is one in which we – including our brains and bodies – are just data zipping about in a hyper-advanced simulation rather than physical brains jacked into a computer. This simulation would have been set up by (presumably) a hyper-advanced species who seem to like to run their own version of The Sims on a Universe-sized scale.

Regardless of the ‘why’, the aspect of this question where at least some scientific inquiry is possible concerns whether or not it would be possible to distinguish anything uniquely simulation-like in our environment that’d give the game away, like a sudden feeling of déjà vu in the world of The Matrix where you can suddenly perceive the fabric of the simulation. However, the major problem which we have to consider when trying to catch a simulation in the act is that to this point we cannot ourselves create even a miniature galaxy and intelligent beings inside it to provide a testable hypothesis.

Beyond popular media like movies and series like Rick & Morty, what do science and philosophy have to say about this oddly controversial subject? According to some, we have already found the smoking gun, while others are decidedly more skeptical.

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That Coin Toss Isn’t Actually 50/50

October 25, 2023 by 19 Comments

A coin flip is considered by many to be the perfect 50/50 random event, even though — being an event subject to Newtonian physics — the results are in fact anything but random. But that’s okay, because what we really want when we flip a coin is an unpredictable but fair outcome. But what if that’s not actually what happens?

There’s new research claiming that coin tosses demonstrate a slight but measurable bias toward landing on the same side they started. At least, this is true of coin flips done in a particular (but common) way. Coins flipped with the thumb and caught in the hand land with the same side facing up 50.8 percent of the time.

The new research builds on earlier work proposing that because of human anatomy, when a human flips a coin with their thumb, the motion introduces a slight off-axis tilt that biases the results. Some people do it less (biasing the results less) and some do it more, but while the impact is small it is measurable. As long as the coin is caught in the hand, anyway. Allowing the coin to fall on surfaces introduces outside variables.

Therefore, one can gain a slight advantage in coin flips by looking at which side is facing up, and calling that same side. Remember that the flipping method used must be that of flipping the coin with the thumb, and catching it with the hand. The type of coin does not matter.

Does this mean a coin flip isn’t fair? Not really. Just allow the coin to fall on a surface instead of catching it in the hand, or simply conceal which side is “up” when the coin is called. It’s one more thing that invites us all to ask just how random is random, anyway?

Electrically controlled behaviors of the lateral α-In2Se3 Fe-FET. a) Hysteresis loop of Id–Vd curve of the planar Fe-FET with 29 nm thick α-In2Se3. b) Band diagram of the ferroelectric switching mechanism. (Credit: Miao et al., 2023)

New Type Of Ferroelectric Memory Constructed Using α-In2Se3 Material

October 19, 2023 by 4 Comments

The ferroelectrical properties of materials have found a variety of uses over the years, including in semiconductor applications. Ferroelectric memory is among the most interesting and possibly world-changing as it could replace today’s fragile and (relatively) slow NAND Flash with something that’s more robust and scalable. Yet as with any good idea, finding the right materials and process to implement it is half the battle. Here is where a recently released paper in Advanced Science by Shurong Miao and colleagues demonstrates a FeFET-based memory cell design using α-In2Se3 material on platinum-based source-drain electrodes. Continue reading “New Type Of Ferroelectric Memory Constructed Using α-In2Se3 Material” →