Physics Stack Exchange
Physics Stack Exchange

Questions tagged [crystals]

Crystals are solid material whose constituents, such as atoms, molecules or ions, are arranged in a highly ordered microscopic pattern, a crystal lattice that extends with regularity in all directions. Use for all crystallography and ordered structure topics.

Crystals are solid material whose constituents, such as atoms, molecules or ions, are arranged in a highly ordered microscopic pattern, a crystal lattice that extends with regularity in all directions. Macroscopic single crystals are usually identifiable by their characteristic geometrical shape, consisting of flat faces with specific orientations.

1007 questions
3
votes
2 answers

Molecular beam epitaxy

Molecular beam epitaxy is a technique of crytal growth that allows controlled deposition of atomic monolayers on a substrate. I have a few questions about this topic that seems not to be treated very much in other questions on this forum. I collect…
Antonio19932806
  • 577
3
votes
1 answer

What happens if we increase the quasimomentum in a crystal above the edge of the Brillouin zone?

If we apply an electric field to a 1D lattice so that the quasimomentum increases as $$\langle\dot q\rangle=eE$$ what happens when we reach the limit $\frac \pi a$? Does the quasimomentum cycle round to $-\frac \pi a$ or does it jump to the higher…
Cameron
  • 1,179
3
votes
1 answer

Does iron get harder after being evaporated and condensed?

I remember hearing somewhere that when iron is vapourised and this iron vapour is condensed, the crystalline structure changes and the iron is much harder than it was before. Is this true and what structure is formed when the iron condenses?
Aerbyt
  • 33
3
votes
1 answer

Construction of first Brillouin zone

For a square lattice with lattice translation vector, $T=a\hat{x}+a\hat{y}$, we find that the reciprocal lattice vectors are given by, $$A=\frac{2\pi}{a}\hat{x},$$ and, $$B=\frac{2\pi}{a}\hat{y},$$ such that the Brillouin zone ranges from…
W. Ryan
  • 241
3
votes
1 answer

Why does a halocline form?

I was doing an experiment over the last couple of days to try to crystallize alum using a thermal gradient. The idea was that solute at the bottom of my container would be dissolved at a higher percentage (I used a coffee mug warmer) because of the…
Ohiovr
  • 157
  • 6
2
votes
1 answer

Show that point group of the reciprocal lattice is the same as the point group of the direct lattice

I have searched days for the answer of this question, but without success. Some background information: A point group must fulfil the mathematical requirements of a group: The product of two operations is another operation in the group The identity…
Anonymous
  • 23
2
votes
1 answer

How many Miller Indices are there?

Are there an infinite combination of (h,k,l) Miller Indices, or would there be some sort of limit to the possible combinations?
Zeno Chen
  • 21
2
votes
0 answers

Why crystal growth tends to be selective for a single species?

Crystals are composed of the same stuff assembled in a periodic fashion. I understand that there are possible and less possible bonds. Like complementary electric charge, ie. things must stick together or at least not repulse each other. However I…
Winston
  • 3,226
2
votes
3 answers

Why is diamond structure not bravais lattice?

Why is diamond structure not bravais lattice? Is it because of interpretation of two f.c.c. structures?
Ka Sikh
  • 115
1
vote
0 answers

How will crystal orientation affect the mobility?

[Refined:] We know that crystal orientation will affect the mobility Mobility Dependence on Crystal Orientation and Strain Engineering. What is crystal orientation? Is there a basic textbook/lecture explaining this concept? For 3d crystals, it seems…
Charlie Chang
  • 207
1
vote
1 answer

Single Crystal Growth- Czochralski process

Cz process operates with two opposite rotations (melt and seed's rotations). How these rotations prevent growing imposed by other facets' directions (Other than that perpendicular to the axis of rotation-of seed?
Eddie
  • 11
1
vote
3 answers

Why lattice constant (unit cell) is always a parallelepiped?

Wikipedia defines lattice constant as physical dimension of unit cells in a crystal lattice. Unit cell is defined as: The unit cell is defined as the smallest repeating unit having the full symmetry of the crystal structure.[4] The geometry of…
Code Complete
  • 255
1
vote
1 answer

What exactly is a basis in the context of crystalline solids?

For the purpose of this question, I'm making the assumption that atoms are fixed in space, and as such possess no vibrational degrees of freedom. A crystalline solid is a solid which exhibits periodicity in the arrangement of its constituent atoms.…
W. Ryan
  • 241
0
votes
0 answers

How can Miller indices be calculated for this reoccuring scenario?

Miller indices are very simple and straightforward for most planes. However, I see a problem for a plane that goes through the coordinates origin. In such a case, the Miller indices should be $(\infty,\infty,\infty)$, because the plane intersects…
100xln2
  • 119
  • 1
0
votes
2 answers

What are normal modes (accoustic/optical modes) in 1d diatomic chain?

Q0: What are normal modes (accoustic/optical modes) in 1d diatomic chain? According to What are normal modes? and wiki, The most general motion of a system is a superposition of its normal modes. 'The modes are normal in the sense that they can move…
Charlie Chang
  • 207
1
2