0
votes
1answer
20 views

simple pores make ceramic opaque

I want to know how a ceramic transparency is mostly affected by the pores, grain boundary, second phases etc. present inside of it, but the major contribution is due to the pores. Let's consider the ...
6
votes
2answers
102 views

Are there materials that get softer with temperature decrease?

Could be there material that begins melting/softening when it's temperature is lowered? I would say no, but I've seen enough physics to know that not always life is so easy. Moreover I think I've ...
3
votes
1answer
42 views

How can one reasonably theoretically model polycrystalline materials?

Many techniques are taught in advanced solid state courses but they are almost all derived for perfectly crystalline materials. For example, band structure really only appears theoretically when you ...
1
vote
1answer
56 views

Why can't a dislocation terminate in the bulk?

We are told that they can only terminate on surfaces, grain boundaries or other dislocations but we are not told why they can't terminate inside the crystal.
2
votes
1answer
71 views

What does (001) Silicon mean?

If someone gives me a thin film of Si, and they tell me it's (001) Si, does that mean that the (001) planes of Si are the ones making up the surface of the film?
0
votes
0answers
44 views

band gaps in tight binding model

What happens at the zone boundaries of the brillouin zones in the tight binding model? How does the band gap originate in the TB model?
0
votes
0answers
47 views

What's the typical material used as a low-k ILD in semiconductors?

Semiconductor companies (namely IBM, Intel, TSMC and etc.) may use different low-k materials as inter-layer dielectric (ILD) in their fabrication process. I'm wondering what is the most typical one. ...
1
vote
0answers
74 views

Is there a derivation of all possible Bravais lattices in 2D and 3D?

Do any of you know a (possibly elegant) derivation of all possible Bravais Lattice and the Crystallographic Group of Lattices in 2 and 3 dimensions? Group theory /abstract nonsense approaches are ...
1
vote
3answers
452 views

when we rub objects together, what determines which material will pick up electrons?

For example We know glass when rubbed by silk will become positively charged while the silk will be charged negative. What exactly makes glass appropriate for losing electrons in that experiment? (
2
votes
2answers
180 views

A few questions about the Fermi Level/Energy

My first question is, how is the Fermi Energy for a material actually determined? I know this derivation, but it seems to say that the Fermi Energy is just based on the electron density (and maybe ...
1
vote
2answers
3k views

Why don't FCC metals have a brittle-to-ductile temperature transition?

I initially thought that it had something to do with the number of slip systems in FCC vs. BCC, but they're both the same.
0
votes
1answer
67 views

Whether Au-Ga-Bi ternary phase diagram be calculated theoretically

Currently, my experiment involves the three elements: Au, Ga, Bi, and I need Au-Ga-Bi ternary phase diagram to explore the ...
9
votes
2answers
236 views

Ferromagnetism with mobile spins

How can electron spins in Iron at room temperature have ferromagnetic order even though they are travelling at very high speeds? One could argue that spin and motion are completely uncorrelated and ...
1
vote
1answer
203 views

If my lattice has an atomic basis, do I also find the reciprocals of the basis vectors to get the reciprocal crystal structure?

That is what my crystal structure looks like. The blue atoms sit on every lattice point (basis vector of $\{0,0\}$) and the red atoms have basis vector of $\left\{{2\over3},{1\over3}\right\}$. The ...
2
votes
1answer
103 views

Is this 2D structure triclinic?

The only rotation axis obvious to me is rotation by 360 degrees, the identity. Vertical mirror planes I've been dicing and cutting it through several planes and I still see none. Yet, the structure ...
1
vote
1answer
211 views

What would be the basis vectors for this 2D crystal structure?

In the above image, I have a 2D crystal structure. The lattice vectors are described by: a = {-1/2, -Sqrt[3]/2}; b = {1, 0}; and the location of atoms A and B ...
2
votes
3answers
1k views

What is the difference between lattice vectors and basis vectors?

Google has not been very useful in this regard. It seems no one has clearly defined terms and Kittel has too little on this.
6
votes
3answers
536 views

Graphene +1 extra carbon bond

I'm not a physicist just a curious mind, so please go easy! I was just watching a BBC Horizon Documentary that featured a piece on the recently discovered material Graphene. One of the facts ...
3
votes
3answers
4k views

Why is copper diamagnetic?

Cu has an unpaired electron in 4s, but it is diamagnetic. I thought that it has to be paramagnetic. What am I missing?
1
vote
1answer
405 views

Learning roadmap for solid state physics [duplicate]

I am a PhD student in mathematics who knows little more about physics than what one learns in high school. For my research on tilings of space and aperiodic order, every now and then I have to skim a ...
0
votes
1answer
110 views

Characteristics of bloch electron in a priodic potential

Effective mass of a Bloch electron in a periodic potential is negative why ?
5
votes
1answer
132 views

Order of magnetic phase transitions

Is there any phase transition occur in paramagnetism to diamagnetism transitions state. What should be the order and how will I calculate the order?
7
votes
1answer
3k views

Why are some materials diamagnetic, others paramagnetic, and others ferromagnetic?

Why are some materials diamagnetic, others paramagnetic, and others ferromagnetic? Or, put another way, which of their atomic properties determines which of the three forms of magnetism (if at all) ...
2
votes
2answers
157 views

What are the specific electronic properties that make an atom ferromagnetic versus simply paramagnetic?

As I understand it, paramagnetism is similar in its short-term effect to ferromagnetism (spins of the electrons line up with the magnetic field, etc.), though apparently the effect is weaker. What is ...
1
vote
1answer
213 views

Nonlinear absorption coefficient and the band gap

How does the nonlinear absorption coefficient depend on the band gap? How can that coefficient be calculated theoretically? (Preferably with an example)
-1
votes
3answers
362 views

Are we crystals?

Can we say that we are crystals because just like crystals we are made up of very small unit (cell) making up almost the same shape (our body) everywhere.
9
votes
3answers
3k views

What determines the color of a pure substance and is it possible to predict it?

I have always wondered why salt is white, water is clear and gold is, well, gold. What determines the color of a substance? Does it have something to do with the electrons? And is it possible to ...