Questions tagged [metals]
The metals tag has no usage guidance.
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Single metal Seebeck effect in a ring in the presence of a magnetic field
According to the usual Seebeck effect, you can make a loop of wire with two different metals, apply a temperature difference between two opposite sites of the ring and measure a current. An answer to ...
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Why does (oxidized) aluminum have a diffuse optical appearance?
Unoxidized aluminum has a shiny appearance like typical metals. However in air aluminum rapidly oxidizes, giving it a more diffuse appearance (or bidirectional reflectance distribution function). ...
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How is it possible for amorphous metal to have good magnetic properties?
Cross-posted on MMSE.
It makes sense to me intuitively that the crystalline structure in, say, grain-oriented electrical steel would yield good magnetic properties. I am envisioning magnetic field ...
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What are strange metals?
What are strange metals?
Are they something that we have really made, or just a theoretical idea?
If they have been prepared in laboratory, then what are their properties (or if they are still a ...
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The relation between surface charge density to wave reflection
We know from Guass law that if an electric field hit perpendicular from dielectric medium to a metal, then a charge density develops on the surface.
$D_{in} - D_{hit} = \sigma$
Where in metal the Din=...
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Why do different metals glow with different colours if all solids have the same emission spectrum?
Why do different metals glow with different colors if all solids have the same emission spectrum? According to my teacher, all solids have the same emission spectrum at the same temperature due to ...
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Calculating the amount of Iron in an unknown solid sample
So I want to take a sample of meteorite and figure out it's iron content. Whilst the overall iron content of the larger meteorite is known, how could I go about figuring this out for a given small ...
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How much will a sheet of gold distort under its own weight? [closed]
The central question I'm seeking an answer to is: what is the minimum thickness required for a rectangular sheet of pure gold, 131cm × 79cm and simply supported on all four sides, so that the centre ...
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Why does liquid mercury start spinning in a magnetic field?
I would think this has something to do with the intrinsic quantumagnetic moment of the metal, but I'm curious if every metal would behave this way in liquid state , and if there are any practical ...
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Hall effect of Metal and Semiconductor [duplicate]
I am pretty much confused in the topic of Hall effect, as it is discussed in Metals and Semiconductor. My question is -
Hall effect in Metals is due to electron as they are in majority, so hall ...
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Can total internal reflection (TIR) occur in metals?
Is it possible to get Total Internal Reflection (TIR) when a light beam hits a metallic surface of complex index $\tilde{n}=n_r+n_ii$? If not, is there a way where a light beam can hit a metallic ...
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What causes aluminum to darken when touched?
The rear side of my graphics card (the side that has the HDMI port) seems to be made of aluminum.
I noticed that whenever I touch it with my clean finger, I leave a dark trail onto it that is around a ...
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Does aluminum darken when exposed to heat?
My graphics card (3060Ti) got these markings that at first looked like mildew to me but after realizing this IO shield (the metal thing) is made of aluminum, I did some research and found out that ...
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Why is a metal pot suddenly iridescent?
I have an old metal pot and for a few days every time I take the pot out of the dish washer it has been quite beautifully iridescent:
Any idea why this suddenly occurred and how I can explain it (to ...
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Are solid materials ergodic systems?
It is stated that a system is considered ergodic if it can access all available states with the same energy in the phase space over long periods of time and that time average and ensemble average of ...
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A question about metal characteristic frequencies
I just noticed that if we mutliply square of plasma frequency for a metal by the electron scattering time, we get another very nice looking characteristic frequency:
$$\omega_p^2 \tau = \frac{\sigma}{\...
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Why are magnesium and calcium crystals, metals instead of insulators/semiconductors?
Consider the outer-most s orbitals for Mg or Ca solid. They will form one band. The 2 electrons in the outer-most shell fill this band. Shouldn't the next p orbital band be above the fermi level and ...
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Is the temperature dependence for electron phonon scattering the same between plasma oscillations and DC transport?
I am examining the temperature dependence of electron phonon scattering in the case of a metal responding to an AC field (forming a plasma oscillation). I have found that for DC transport, the ...
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Pushing molten metal through 0.1 mm hole [closed]
is it possible to push molten metal (eg, titanium), through 0.1mm bore and what would be the force required for a steady & consistent stream of metal?
Any mathematical formulas/theory is good.
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Electric field deep inside metals in two non-static situation
Consider the following two non-static situations.
When we connect a dc or ac source across a metal, an electric field exists inside the metal which causes the electrons to flow through the metal ...
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Is an object's pressure on a surface, affected by the type of surface?
Is an object's pressure on a surface, affected by the type of surface. For example, if a chunk of metal gave a pressure of $2800 \ pa$ on a table, would it still give a pressure of $2800$ on dust/sand,...
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Why doesn't the saturation photoelectric current depend on frequency?
From my understanding, even if the frequency of a photon is above the threshold frequency, it is not necessary that an electron gets ejected as the photon may have been absorbed by a metal atom ...
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Brewster's angle for Metal?
As metal has a high refraction index, it is possible to have Brewster's Angle for Metal when the light incident from the air? Is it possible to derive from any formula?
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Specific heat of mercury and water?
My doubt is , if mercury is denser than water , then why specific heat is lesser of mercury than water , means mercury heat faster than water , if mercury heat faster than water then again , why ...
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Magnetic static field simulation software to model metals in Earth's magnetic field
I need to model the effect of steel or iron objects of a given shape disturbing Earth's magnetic field like shown in the pic below. The software, providing a solution, should be free and open source. ...
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Lindhard theory: What effects are observed between screening and plasma oscillations regimes?
Let us consider metals in the presence of an electromagnetic field.
In the stationary regime (frenquency $\omega=0$), we have Thomas-Fermi screening, charges build up at the surface to cancel the ...
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Can electrons absorb photons?
I see two broadly opposite answers to this question. One is that electrons can absorb photons, and one is that electrons can't absorb photons (see How many photons can an electron absorb and why?).
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Why do some metals and metal alloys have Fatigue Limits, and others do not?
I recently learned of Fatigue Limits, defined as "the stress level below which an infinite number of loading cycles can be applied to a material without causing fatigue failure." Somewhat ...
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Acoustic absorption coefficient of Metals
Which non toxic Metals have the lowest Acoustic absorption coefficient?
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What is the historical context to specify resistivity of metals in $\mu\Omega$cm instead of $\mu\Omega$m?
The resistivity of metals usually lies in the range 1-10 $\mu \Omega$cm at room temperature as given in Chapter 1 of Ashcroft's and Mermin's Solid State Physics. Why is it not given in $\mu \Omega$m. ...
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Why silver reflectivity decreases at around 350
This picture is from the site:https://www.zmescience.com/other/feature-post/gold-color-relativity/
I was wondering why the reflectivitiy of silver goes to 0 at around 350 nm. I understand why for gold ...
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Why holes are better in storing both valley and pseudospin information?
Recently I attended a class about transition-metal dichalcogenides (TMDC) and, during the lecture, the professor said that holes are better than electrons in storing both pseudospin and valley ...
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Would a vibrating metallic and charged surface emit electrons?
Consider a metallic object under an intense electric field so its electrically charged in its surface. If the object is set to vibrate could it emit electrons?
This effect would be similar to ...
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The time scale of charge accumulation or polarization by applied electric fields
When electric fields are applied to metal or dielectric, as a response, the charge accumulation (in metals) or the polarization (in dielectrics) is induced. I wonder how fast the response is complete. ...
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Why do not all the semimetals turn into the excitonic insulators?
I want to know the condition for forming the excitonic insulator.
When the binding energy of the exciton, $E_b$, overcomes the band gap, the system becomes the excitonic insulator. If so, all ...
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Why is Fermi energy considered most probable energy that electron posses in solids?
It can be seen in graph that probability of electron occupying a energy level below $E_{f}$ is $>\frac{1}{2}$, then why it is said that Fermi energy is considered as most probable energy that ...
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Can this laser cofiguration be used to penetrate armoured bodies?
I asked the same question before but as it was stated as unclear I hope that with several corrections the question is more clear now. As the question is more theoretical than engineering I posted here....
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Second-Order Perturbation in electron gas
I was trying to figure out the solution to exercise 1.4 on Quantum theory of many particles systems by Fetter & Walecka and I read through this question and its answer. But a point made in both ...
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Why do most metals have high thermal expansion coefficient although their thermal conductivity are generaly high?
the relationship between thermal conductivity and thermal expansion in metals. Why do most metals have high thermal expansion coefficient although their thermal conductivity are generaly high? Please ...
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Molten metal flow due to high currents
It is mentioned in the book "Ampere-Neumann Electrodynamics of Metals", Peter Graneau, that Carl Hering in 1923 operated furnaces by passing high currents through the molten metal pool. He ...
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Iridium carbides in stainless steel alloys
Has there ever been any high carbon stainless steel made with iridium as one of the alloy components? Is there any research in this direction?
There is a paper from 2016 comparing various iridium ...
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What does the electric field from a off-center charge inside of a metal sphere look like?
Consider a uncharged metallic sphere with a charge inside of it but not in the center, e.g. $0.5$radius upwards. What does this electric field look like? Without the sphere it is easily calculated but ...
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Relation between Fermi surface and Fermi velocity
Is there a direct relation between the Fermi velocity and the Fermi surface? Can one reconstruct the Fermi surface if the full angular distribution of the Fermi velocity is known?
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Vanishing electric field inside a conductor implies vanishing charge density but there is a puzzle
If we place a metallic conductor in a static, external electric field, the free electrons inside the conductor will move opposite to the external field leaving the immobile positive ions (nucleus+core ...
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Permittivity vs resistance of metals and skin depth
I'm asked to estimate the skin depth of copper at a certain frequency, but in deriving the equation for skin depth we basically need to assume $-\omega^2\varepsilon+j\omega\sigma\approx j\omega\sigma$,...
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What would happen on an atomic level to mercury in a microwave?
I'm not sure why I was thinking of this, but I did and I couldn't think of an equivalent physical model to relate microwaved liquid Mercury to.
Polar substances are heated by dielectric heating, the ...
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Are there charge fluctuations in band insulators?
Consider a one-dimensional non-interacting Hubbard Hamiltonian:
$$
H=-t\sum_{\langle i, j \rangle}\sum_{\sigma=\uparrow,\downarrow} \left(c_{i,\sigma}^\dagger c_{j,\sigma} +\mathrm{h.c.} \right)
$$
...
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Periodic boundary condition (Born-Von Karman): does the size of the cube matter?
Periodic boundary conditions are chosen to faithfully represent the dynamical situation of electrons flowing through the metal. It's a better picture than the stationary wave one. We imagine a cube of ...
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Valence and conduction band definition in metals
In the textbook examples, the band character (VB and CB) of semiconductors is explained by their location above (CB) or below (VB) the Fermi level. In metals however, the valence and conduction bands ...
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What is the difference between the superconducting energy gap, order parameter, and pair potential?
I often see these terms used interchangeably in literature. However, in papers that discuss the proximity effect in bilayers, I'll see statements saying the order parameter is spatially dependent but ...
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