Questions tagged [metals]
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386
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Does metallic bond increase with the increase of atoms?
So, metallic bond doesn't form between two atoms, it forms when there are a large number of atoms.
However, the establishment of metallic bond was statistical, thus there might be a time where ...
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0answers
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Is solar radiation at earth's surface under STC sufficient to eject electrons from aluminum?
As I understand, sunlight energy that reaches the ground is around 4% ultraviolet, 43% visible light, and 53% infrared. Temperature, solar irradiance, and other factors are at play so let's assume ...
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2answers
36 views
What causes the photoelectric vs photovoltaic effect?
In the photoelectric effect, electrons are physically ejected from the material. In the photovoltaic effect, electrons are knocked out of their atomic orbitals but remain within the material.
What ...
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0answers
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Rutherford scattering experiment, part 2
This question is a continuation of my previous question Rutherford scattering experiment, part 1 , but can be considered independently.
Around 1906-1914 several classical experiments on scattering of $...
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1answer
42 views
Rutherford scattering experiment, part 1
Around 1906-1914 several classical experiments on scattering of $\alpha$-particles on gold and platinum foils have been performed by Rutherford, Geiger, and Marsden. In standard literature on the ...
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6answers
4k views
Why do metals have free electrons?
Throughout my highschool classes, I have been made to learn that metals have free electrons that's why they are able to conduct electricity.. But I never understood why. Is that related to metallic ...
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3answers
154 views
Why is the heat flow in metals slower than the current flow?
When we apply a voltage across a metallic conductor, the current starts to flow almost instantaneously. But when a temperature difference is established across the same conductor, the flow of heat is ...
3
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1answer
42 views
(Fundamental) difference of Seebeck effect for metals and semiconductors
In which way is the Seebeck effect different for semiconductors from metals and why is it greater? What is the difference in the underlying physical principle?
My knowledge so far is: Bring two ...
3
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1answer
40 views
What is plasmon really? Is it a charge density wave of electron gas or an EM wave that exists across the metal surface?
Sometimes plasmons are defined as collective plasma oscillations of the free electron gas in a metal. Therefore, plasmons must be a periodic modulation of electron charge density in the metal. But ...
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1answer
53 views
Screened Coulomb potential in metals
One of the reasons why we can neglect electron-electron interactions in metals is the fact that their coulomb interaction is screened. I'm confused about the nature of this screening. In the ...
11
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1answer
214 views
Why is crystalline graphite black yet shiny?
I am unable to find images of pure crystalline graphite with high confidence, but based on various sources I believe that it should actually be both black and shiny, in the sense that it reflects much ...
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2answers
46 views
The Electric Pressure Bomb: Can a conductor rupture due to its own electric pressure?
So I conducted a though experiment where I take a hollow spherical conductor and beef it up with a lot of electric charge. Here, I have ignored the ionization of air due to that huge amount of charge. ...
4
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3answers
58 views
How do electrons in metals manage to have zero acceleration in constant $E$ field (as in a DC circuit)?
From Newton's second law, a charged particle driven by a constant electric field should move with a constant acceleration. But electrons in a circuit acquire a steady average velocity which gives rise ...
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0answers
28 views
Is there an easy way to predict whether a given element will crystallise in the FCC or in the HCP structure?
I noticed, reading the solid state physics book by Ibach & Lüth, that the majority of elements crystallize in a handful of space groups:
I highlighted face-centered cubic (FCC) structures in ...
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1answer
24 views
What does work function of metal exactly mean in photoelectric emission? [duplicate]
When a metal surface is illuminated with light of appropriate frequency so as to cause photoelectric emission, when does the work function of the metal come into play? Is it the energy required to ...
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0answers
35 views
Does magnetism of metals increase when they are irradiated?
Metals have magnetic properties because they are crystal structures with unpaired electrons moving around through them, these unpaired electrons have a net spin. Does irradiating a metal increase the ...
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0answers
14 views
Work function and surface and lattice binding energy
How work function and surface and lattice binding energy are related in a metal?
I need to estimate with SRIM the changes of the work function of a gold slab after bombardment of ions, but SRIM ...
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1answer
41 views
Deriving Drude Theory from Plasma Fluid Equations
Does anyone have experience in looking at Drude theory from the perspective of plasma physics instead of the standard, condensed-matter, "electrons in a metal" sort of thing and can point ...
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1answer
46 views
How do I compute the cohesive energy of a 1D Solid (in Tight Binding) due to electrons?
The cohesive energy of a solid is the (average) energy required to isolate the atoms of a solid, which means it's given by the difference between by the energy of solid and the energy of the isolated ...
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2answers
35 views
Explanation of the concavity of conduction band and valence band of semiconductors at $k=0$
For semiconductors, the conduction band is often drawn with a positive concavity at $k=0$ while the valence band below it is drawn with a negative concavity at $k=0$. Why is this figure never flipped ...
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1answer
196 views
Physical significance of electrons with negative effective mass. Are they holes or what?
For metals,
the conduction band is less than fully filled,
the effective mass $m^*=\hbar^2\Big(\frac{d^2E}{dk^2}\Big)^{-1}$ is positive for the interval $k\in[-\frac{\pi}{2a},+\frac{\pi}{2a}]$ of ...
10
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2answers
701 views
Why do group II elements conduct?
Looking at the periodic table, group II elements like magnesium are known to be metallic, and yet they have full outer shells. So this means they should have full (valence) bands.
Now, last time I ...
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1answer
35 views
Why is the dielectric constant of copper plate infinite?
There was a question asking the electrostatic force between two charges if a a copper plate of thickness d/2 is kept between them. The effective force was 0. How?
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0answers
20 views
Describing the shape formed by crushing malleable cubes
I just watched a video of cubes of various metals being crushed by a hydraulic press (on the hydraulic press channel). Two of the cubes (made of somewhat stronger materials) deformed into an ...
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0answers
20 views
Hall coefficient for metals negative
I am wondering why the Hall coefficient for Al is negative, I am thinking about holes (I understand how holes word in semiconductors, but I can not use that because metals have no bandgap...), but I ...
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2answers
51 views
What makes seasoned cast iron non-stick?
I get how Teflon works, but am curious how the act of seasoning cast iron makes it non-stick. Does this also work for other metals besides cast iron?
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1answer
45 views
Temperature dependency of electron density in metals
I wanted to know how the electron density in metals behaves with temperature. I couldn't really find an answer online so I searched through my x-years old scripts and, surprisingly, I found a sentence ...
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0answers
31 views
Does the Mott metal-insulator transition occur with increasing or decreasing density of valence electrons?
When reading about the Mott metal-insulator transition, it has not become clear to me if the transition from a metal to an insulator occurs with increasing or decreasing density of valence electrons.
...
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1answer
50 views
Metal-insulator transition (material properties)
When studying about metal-insulator transitions, I was wondering which material properties can give direct information about this phenomena. Also, what information can be derived from these properties....
2
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1answer
54 views
Why free electrons do not leave the surface of metal?
In metals free electrons can move freely over the whole piece of metal, but they do not leave it. Moreover in electrified metals the extra electrons are located near the surface of the metal, but do ...
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0answers
97 views
Does the Mott insulator exist?
The Mott insulator is a system that due to strong electron-electron interactions is an insulator which be a metal by formal charge counting of electrons in the unit cell.
Often, the Mott insulator is ...
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0answers
36 views
How is absorption integrated in the simple Drude model?
What is the physical process of absorption in the Drude model?
As far as I understood in the Drude model you only consider the electrons as classical particles and frozen ions. No other particles ...
0
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1answer
22 views
p- and n- contact metal difference
I'm reading an article about some electronic components and the authors specify that they used p- and n- contact metals, but without giving details about those metals, or what material are they really....
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2answers
104 views
Why are there electron and hole currents in semiconductor, but only electron current in metal?
Why are there electron and hole current in semiconductor, but only electron current in metal ?
I know that in metal there is an overlap between valence and conduction band,
while for semiconductor, ...
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3answers
333 views
Do metals at low temperature follow Ohm's law?
I think metals at low temperature do not follow Ohm's because of superconductivity. Is it true? What about metals at high temperature?
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2answers
84 views
Can we understand the strong reflectivity of metals from band theory?
I know that solids, including metals, have electronic bands and bandgaps. If we consider some typical metal such as copper, we know that it strongly reflects visible light. From the point of view of ...
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1answer
35 views
Is it possible for aluminium alloys in an explosion to become pure elemental powder particles?
I am making a paper about metals and would like some help with this issue.
If you have some kind of explosion, is it then possible for aluminium alloys to become powder particles?, if yes, can they ...
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1answer
22 views
Why do (semi-)conducting materials absorb microwaves at their cyclotron frequency? - Cyclotron Resonance Technique
I am currently studying third year physics - more specifically a solid state course.
It was mentioned that in order to determine the effective mass of an electron in the nearly-free-electron model ...
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1answer
57 views
Is it right to conclude that Aluminium has free electrons from this?
I bought Dominos Choco Lava Cake and I had to warm it in my microwave oven. I could see that the cake was wrapped in aluminium foil, I put it in inside the oven and when I switched it on electricity ...
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1answer
98 views
How is an Eddy current separator actually getting the particle fly off?
I am currently trying to understand the eddy current separator on a physical level, but unfortunately I have a few uncertainties to resolve. I don't quite understand what is ultimately the reason why ...
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2answers
41 views
Comparing energy band diagram for metals, semiconductors and insulators
The energy band diagram is a model for describing why an insulator is not a good conductor compared to a semiconductor: in the first case, electrons would need to pass a very large band gap in order ...
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2answers
38 views
Quenching a metal spring with coffee
“With” meaning involving, not in. My coffee maker isn’t draining properly anymore, so the drip basket is overflowing. The spring that lets coffee flow out at the right rate seems to have stiffened ...
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2answers
361 views
Effective mass for metals
How can I calculate effective mass for of the electrons in $Al$ and $Ca$? I did real from some sources and they were mentioning that it could be evaluated from density of states but how? Also is ...
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1answer
139 views
Materials intermediate in density between osmium and neutronium [closed]
The densest elements on Earth are metals. Osmium is the most dense. The densest matter in the Universe is Neutronium which is not an element but degenerate matter. If we put Osmium and Neutronium on ...
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1answer
24 views
Can an electric magnet be a substitude for a magnet to test a metall?
For instance I have to check if certain metal is a ferromagnetic metal. Can I use an electric magnet instead of non-electric one?
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64 views
Conduction Theory [closed]
Why the conductivity of Metal increase with a decrease in temperature, semiconductor increase with an increase in temperature and alloys remains the same ?
Is it due to the following reasons?
...
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0answers
45 views
What happens to atomic spacing when a spring or solid material is deformed?
I am wondering if there is a ever a situation where atomic spacing is decreased when a solid material is deformed? I am aware that atomic layers slide over one another in malleable metals and that ...
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1answer
65 views
Thermal expansion of a rectangular metal shape
This question is inspired by this interesting answer which left me somewhat uncomfortable for the following reasons:
Suppose we have the following notched metal shape:
Following the linked answer, ...
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0answers
14 views
Why Metal-induced gap states don't apper at the interface of metal-metal?
I'm sorry for the silly question. I'm reading the article of Meta-induced gap state(MIGS) on the wikipedia. It says "MIGS appear when we break the transverse symmetry. At the interface of metal/...
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Does heating a jar lid significantly expand the metal?
The heat from hot water expands the air inside the jar relieving the amount of negative pressure inside the jar. Hot water may additionally help to loosen any sticky material inside the jar lid from ...
