Number of modes for a 2d crystal

  • Context: Graduate 
  • Thread starter Thread starter kuecken
  • Start date Start date
  • Tags Tags
    2d Crystal Modes
Click For Summary
SUMMARY

The discussion centers on the vibrational modes of a 2D crystal with one atom per primitive unit cell. It concludes that there are 2N discrete vibrational modes, where N represents the number of atoms in the unit cell, confirming the presence of one transverse and one longitudinal mode for each k-vector. Additionally, it is established that the crystal exhibits two acoustic branches, affirming the initial assumptions made by the participants.

PREREQUISITES
  • Understanding of 2D crystal structures
  • Familiarity with vibrational modes in solid-state physics
  • Knowledge of k-space and its significance in phonon dispersion
  • Basic concepts of acoustic and optical branches in crystals
NEXT STEPS
  • Research the derivation of vibrational modes in 2D crystals
  • Study the concept of phonon dispersion relations
  • Explore the differences between acoustic and optical branches in crystal lattices
  • Learn about the implications of vibrational modes on material properties
USEFUL FOR

Physicists, materials scientists, and students studying solid-state physics, particularly those interested in the vibrational properties of 2D materials.

kuecken
Messages
17
Reaction score
0
Hi, I have problems with the following:

Number of modes for a 2d crystal with one atom per primittive unit cell.

1. Number of discrete vibrational modes?
Should there be 2N of them? That is what I come up with if I think of one transverse and one longitudinal mode for each k. But I am unsure.

2. So am I able to obtain two branches from this crystal?
Both of them are acoustical?

Thank you :D
 
Physics news on Phys.org
Yes, both conclusions seem to be correct to me.
 
  • Like
Likes   Reactions: 1 person

Similar threads

Graduate Mode matching to an optical cavity
  • · Replies 0 ·
Replies
0
Views
3K
Graduate Relating molecules, atoms to number of optical branches (modes)
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Help with determination of crystal orientation
  • · Replies 5 ·
Replies
5
Views
2K
Graduate Confused about selection rules in optical transitions
  • · Replies 0 ·
Replies
0
Views
2K
Undergrad Questions on Debye's Model of solids
  • · Replies 1 ·
Replies
1
Views
2K
Graduate What Are Acoustical and Optical Branches in Crystal Waves?
  • · Replies 1 ·
Replies
1
Views
2K
Graduate What Are Acoustic Phonon Modes in Calculating Heat Capacity of a Solid?
  • · Replies 4 ·
Replies
4
Views
4K
Graduate Phonon-Phonon Coupling (Different Wave Vectors)
  • · Replies 11 ·
Replies
11
Views
4K
Graduate Bonds in Semiconductor crystals
  • · Replies 2 ·
Replies
2
Views
3K
Finding Total Number of Optical Field Modes for Visible Light
  • · Replies 2 ·
Replies
2
Views
2K