Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physics > Condensed Matter Physics > Flashcards

Condensed Matter Physics Flashcards

1
Q

How do you find the volume of the primitive cell?

A
  • Need the primitive translation vectors of the crystal lattice a1, a2, a3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do you find the primitive translation vectors of the reciprocal lattice b1, b2, b3?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the structure factor?

A
  • fj is the atomic form factor
  • generally for the basis, f is used for the form factor of the atom (that is identical in the basis)
  • xj, yj, zj are the posns in the basis of the idential atoms
  • e.g. for the bcc basis atoms are identical at 0, 0, 0 and 1/2, 1/2, 1/2
    • so S(v1v2v3) = f{1 + exp[-π(v1+v2+v3)]}
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do you calculate the structure factor for a certain structure?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the atomic form factor?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the atomic form factor if charge distribution is spherically symmetrical about the origin?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How to calculate the interplanar distance?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the equation for electric conductivity?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is the KE of a free e- at corner of first zone higher than that of an e- at midpoint of a side face of the zone in 2D? By what factor is it higher? And what is the factor in 3D?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you calculate the Fermi energy and density of states of a free e- gas in 1D and 2D?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the energy eigenvalues of a 3D gas of free e-s at 0K?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the relation connecting pressure and volume of an e- gas at 0K?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are 2 ways of entering reciprocal space?

A
  • diffraction
  • Fourier analysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Bragg’s law?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do energies of photon, neutron and electron compare? And what does wavelength vs energy graph look like?

A
  • photon energy = keV
  • neutron energy = 0.01 eV
  • e- = 100 eV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is extinction?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a Brillouin zones?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is spallation?

A
  • fast protons e.g. 1 GeV approaching Pb
    • intra-nuclear cascade with cascading particles then inter-nuclear cascade
    • or highly excited nucleus
      • then evaporation
  • [still don’t really know what this is]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is fission? Why are neutrons used? [don’t know why there are words listed under neutrons]

A
  • neutron hits 235 U then fission of excited nucleus
    • chain reaction by moderated nucleus
  • neutrons
    • light elements
    • magnetism
    • high penetration
    • dynamics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a coolidge tube?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a rotating anode?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a Synchrotron?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is brilliance in X-ray? And Moore’s law?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do the width, area, position and background of a counts vs θ-θBragg show?

A
  • posn => unit cell
  • area, intensity => atomic arrangement
  • width => corrections
  • background => defects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How are Debye-Scherrer Cones scattered?

A
  • powder diffraction
  • scan 2θ or λ then use Bragg’s law (λ=2dsinθ)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is Low Energy Electron Diffraction (LEED)?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the different types of bonding?

A
  • van der Waals e.g. crystalline argon
    • neutral atoms with closed e- shells
    • fluctuations in charge distributions
  • ionic e.g. sodium chloride
    • e-s transferred and ions held together by attractive electrostatic forces
  • metallic e.g. sodium
    • valence e-s taken from alkali atoms to form a communal e- sea
  • covalent e.g. diamond
    • overlapping parts of e- distribution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the different of solids?

A
  • amorphous
    • no recognisable long-range order
  • polycrystalline
    • completely ordered in segments
      • grain/domain
      • grain boundary
  • crystal
    • entire solid made up of atoms in orderly array
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the difference between conventional and primitive cells?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the five distinct 2D Bravais lattices?

A
  • oblique
  • square
  • triangular
  • rectangular
  • centred rectangular
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the 14 Bravais lattices in 3D? 4 types of unit cell( P = primitive, B = body-centred, F = face-centred, S = side-centred) + 7 crystal classes

A
  • cubic
    • P, B, F [most important]
  • tetragonal
    • P, B
  • orthorhomic
    • P, B, F, S
  • hexagonal
    • P
  • trigonal
    • P
  • monoclinic
    • P, S
  • triclinic
    • P
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Give examples of simple cubic, BCC, FCC, Hexagonal Closed Packed (HCP), diamond lattice, zinc blende structure

A
  • simple cubic (rare) e.g. Po
  • BCC e.g. Na, K, Fe, V, Cr
  • FCC e.g. Al, Cu, Ni, Au, Pt, Ir, Ar, Xe, Kr
  • HCP: ABABAB
    • FCC: ABCABC
    • Zn, Ti, Co
  • diamond e.g. C, Si, Ge
  • zinc blende structure e.g. GaAs, GaP, InAs + many more
    *
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are nanowires?

A
  • zinc blende: ABC
  • twin: BAC
  • wurtzite: AB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What do (100), (110), (111), (200), (1-00) planes look like in a cubic crystal?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How does thermal evaporation work?

A
  • high vacuum created by diffusion pump; backed by rotary pump
  • filament boat filled with evaporat
  • clamps connected to high current source
  • path of vapour is upwards towards the substrate holder and sample
    • crystal detector is on top of the sample where the substrate table is
  • glass bell jar contains the vapour
36
Q

How does sputtering work?

37
Q

How does Pulsed Laser Deposition (PLD) work?

38
Q

How does melt spinning work? Amorphous metals

39
Q

How do you grow crystals?

A
  • silicon does not occur alone in nature (man made)
  • heating SiCl4 in hydrogen atmosphere to yield pure Si (polycrystalline)
    • SiCl4 + 2H2 -> 4HCl + Si
  • two methods to turn polycrystalline Si into single crystalline Si ingot
    • Czochralski (CZ)
      • melt high purity Si in a quartz crucible
      • dips one end of seed on molten liquid
      • seed slowly rotated and pulled
      • by controlling temp. difference, seed crystal slowly grows
    • Float zone (FZ)
      • keep poly-Si rod and seed crystal vertically face to face
      • partially melt by inducted heating from high RF power
      • molten zone is rotated and gradually moved up
      • entire polycrystalline rod is converted to single crystal
40
Q

What is molecular beam epitaxy?

41
Q

How do you grow nano wires?

A
  • flux of gold condense to nanosize particles at surface of wafer
  • enhanced growth of III and IV materials catalysed by gold particles
  • freestanding III-V NWs with diameters specified by the catalyst
    • what does NWs stand for? what are III and IV materials?
42
Q

How does Scanning Tunneling Microscopy (STM) work?

43
Q

What are the defects and dislocations in crystals?

A
  • edge dislocation
    • Schottky
    • Frenkel
  • screw dislocation
44
Q

What is there to know about impurities and alloys? What are ordered alloy phases?

A
  • solid soln
    • Si/Ge
  • immiscible
    • Ag/Cu
  • ordered alloy phases
    • disordered Cu3Au (“average” gold-copper atom)
      • disordered because can’t distinguish?
    • ordered; can tell gold and copper atoms apart (copper at centre of faces)
    • I-tetragonal (what is this?)
      • AuCu (copper at centre of sides instead of fcc)
45
Q

What is the Dulong and Petit heat capacity?

A
  • older than Einstein model (1907) and Debye model - acoustic phonons (1914)
46
Q

What is the dispersion relation?

47
Q

What are phonons?

A
  • Quasiparticles in QM that describe a quantised mode of vibration in a solid
    • like sound-particles (oversimplified)
48
Q

What are optical modes? What are acoustical modes?

A
  • figure shows a transverse optical and acoustical acoustic waves in diatomic linear lattice; particle displacements at same wavelength
49
Q

What are optical and acoustical branches of the dispersion relation for a diatomic linear lattice? And the limiting frequency?

A
  • limiting frequencies at K=0 and K = Kmax = π/a
    • lattice constant a
50
Q

What is inelastic neutron scattering?

A
  • triple axis geometry
51
Q

What is lattice energy and specific heat?

A
  • Dp(ω) = density of states
52
Q

What is the Born-von Karman periodic boundary condition for linear chain?

A
  • u ( [N+1] a) = u(a); u(0) = u(Na)
    • like a ring
  • length L=Na
53
Q

How do you integrate in 2D square lattice with Fourier space? [answer doesn’t really explain it tbh]

A
  • allowed values in Fourier space of phonon wavevector K for square lattice of lattice constant a
    • periodic boundary conditions applied over a square of side L = 10 a
  • one allowed value of K per area (2π/L)2 = (2π/10a)2
    • so within circle of area πK2, number of allowed points is πK2(L/2π)2
54
Q

What is the Debye model?

A
  • assume only acoustic wave excited
    • ω = vk
55
Q

How does thermal expansion occur?

A
  • as temp. increases, atomic vibration amplitude also increases
    • cause an increase in bond lengths (avg. distance betwen atoms)
    • hence leads to thermal expansion
56
Q

What is thermal conductivity?

A
  • it is similar betwen an ideal gas and phonons
57
Q

What is the difference between normal process and Umklapp process in thermal conductivity?

A
  • normal process
    • G=0 => cause 0 thermal resistance directly
  • Umklapp process
    • G = reciprocal lattice vector = 2π/a hence not zero => cause thermal resistance
  • selection rules
    • K1 = K2 + K3 + G
    • ћω1 = ћω2 + ћω3
  • ​Dependance on crystal size (curve moves up before the peak)
58
Q

What are trapped ion chains?

A
  • EM fields in a “Paul trap” hold a small number of atomic ions in free space
  • ions repel each other due to Coulomb interactions i.e. their motion is coupled
  • ions can be interrogated and “kicked” using laser beams
59
Q

How are phonons be used for “quantum logic” clocks?

A
  • “quantum logic” clocks is an optical atomic clock: tune laser to a transition frequency of an ion & count oscillations of laser’s light field
    • know laser is at resonance with atom
      • when transfer electronic excitation from Al+ to Be+ using a “phonon bus” (excite Al+ if at resonance then convert into phonon then convert to Be+ excitation)
60
Q

How are electron gas formed?

A
  • isolated atom have valence atoms
    • whereas in a metal, nucleus and ion core retain their configuration in the free atom
    • but valence electrons to form electron gas?
61
Q

What is the Drude Model in Ohm’s law?

62
Q

What does the Fermi-Dirac distribution look like at different temps?

63
Q

What are the electronic states in reciprocal space (is that k space)?

A
  • what’s k anyway?
64
Q

What are the equations for Fermi wavevectors, Fermi energies and Fermi velocities?

65
Q

What is the density of states (based on Fermi energy?) as a function of ε (which I’m guessing is energy)?

66
Q

What is X-ray emission spectroscopy? What is photoelectron spectroscopy?

A
  • width of the spectrum = Fermi energy
67
Q

What is the specific heat of the electrons?

68
Q

How do specific heat capacities of silicon and copper compare in Dulong and Petit law and Debye model?

69
Q

What is a Fermi sphere?

A
  • encloses occupied e- obritals in k space in ground state of e- gas?
70
Q

What is the Drude-Sommerfeld Model?

A
  • eqm Fermi surface has empty states below Fermi energy
  • a displaced Fermi surface has full states above Fermi energy
    • displacement is eEτ/ћ
71
Q

What is the Umklapp process?

A
  • electron-phonon scattering
  • 2 Fermi spheres in adjacent zones
    • construction shows the role of phonon umklapp processes in electrical resistivity
72
Q

What is the Hall effect? Give its equation of motion.

A
  • B field applied in z direction
    • section perp. to z axis; drift velocity starts up
    • then section perp. to z axis; drift velocity in steady state when Ey occurs
73
Q

What happens to the Hall effect in steady state?

A
  • steady state => d/dt = 0
74
Q

What is the Hall coefficient?

75
Q

What is Weidemann-Franz law?

76
Q

What do the energy bands diagrams for metals, semiconductors and insulators look like?

77
Q

What is Bloch’s theorem?

78
Q

What is the general solution to the central equation?

79
Q

What is the nearly free electron model?

80
Q

How do you measure band structures?

A
  • angle resolved photoemission
81
Q

How do you construct 2D Fermi surfaces?

83
Q

What is the effect of weak potential?

84
Q

What is LCAO?

Physics (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions