Condensed Matter & Materials Physics

Hardness

A material's resistance to localized plastic surface deformation induced by mechanical scratching, abrasion, or indentation.

H = Load / Indentation Surface Area (Mohs, Vickers, Rockwell) MPa or GPa (Mohs scale 1 to 10)

Intrinsic Semiconductor

An ultra-pure semiconductor crystal containing no significant dopant impurity species, where carrier concentration is determined purely by…

n = p = n_i = √(N_c N_v) e^(-E_g / (2 k_B T)) cm⁻³ (Carrier Density)

Condensed Matter & Materials Physics

Josephson Effect

The quantum tunneling of Cooper pairs across a thin insulating barrier separating two superconductors (a Josephson junction).

I = I_c sin(Δφ), V = (ℏ / 2e) (dΔφ / dt) mA (Current), μV (Voltage)

Condensed Matter & Materials Physics

Liquid Crystals

States of matter possessing physical properties intermediate between conventional isotropic liquids and ordered crystalline solids.

Nematic Order Parameter S = ½ ⟨3 cos² θ - 1⟩ Dimensionless Orientational Order S

Condensed Matter & Materials Physics

Magnetic Domains

Microscopic regions within a ferromagnetic material where atomic magnetic moments are aligned parallel in a uniform direction.

Domain Wall Energy E_total = E_exchange + E_anisotropy μm to mm (Domain Size)

Condensed Matter & Materials Physics

Majority & Minority Carriers

The classification of charge carriers in a doped semiconductor based on their relative concentrations.

N-Type: n_majority = N_D, p_minority = n_i² / N_D cm⁻³ (Carrier Density)

Condensed Matter & Materials Physics

Malleability

A material's physical ability to deform plastically under compressive stress without cracking, typically tested by hammering or rolling…

Compressive strain tolerance without cracking Qualitative / Quantitative Plastic Strain

Condensed Matter & Materials Physics

Martensitic Transformation

A rapid, diffusionless solid-state phase transformation driven by collective lattice shear displacement of atoms.

Diffusionless shear transformation: Austenite (FCC) → Martensite (BCT) Transformation Temperature M_s

Condensed Matter & Materials Physics

Meissner Effect

The active expulsion of magnetic flux from the interior of a superconductor as it cools below its critical temperature T_c.

B_internal = 0, M = -H (Perfect Diamagnetism) T (Magnetic Flux Density B)

Condensed Matter & Materials Physics

Metamaterials

Artificially engineered composite structures designed with subwavelength resonant features that display electromagnetic properties not…

n_refractive = - √(ε_r μ_r) (Negative Refractive Index) Dimensionless Index n < 0

Condensed Matter & Materials Physics

Miller Indices

A standardized three-integer crystallographic notation system (h k l) used to specify direction vectors and orientation of planes in a…

(h k l) = Reciprocals of lattice axis intercepts Dimensionless Notation System

Condensed Matter & Materials Physics

N-type Semiconductor

An extrinsic semiconductor in which pentavalent donor impurities create an excess concentration of free electrons as majority charge…

n ≈ N_D ≫ p, n p = n_i² cm⁻³ (Electron Concentration)

Condensed Matter & Materials Physics

Non-Newtonian Fluids

Fluids whose shear viscosity changes depending on applied shear rate, stress magnitude, or shear history.

τ = K (du / dy)^n (n ≠ 1) Pa·s (Apparent Viscosity η)

Condensed Matter & Materials Physics

P-type Semiconductor

An extrinsic semiconductor in which trivalent acceptor impurities create an excess concentration of positive holes as majority charge…

p ≈ N_A ≫ n, n p = n_i² cm⁻³ (Hole Concentration)

Condensed Matter & Materials Physics

Peltier Effect

The absorption or emission of heat at the junction of two dissimilar electrical conductors when an electric current flows across it.

Q_rate = Π_AB I = (S_A - S_B) T I W (Cooling / Heating Rate)

Condensed Matter & Materials Physics

Phonon

A quantized collective vibrational wave excitation traveling through the periodic atomic or molecular lattice of a solid.

E = (n + ½) ℏ ω, p_crystal = ℏ q eV or J (Phonon Energy)

Condensed Matter & Materials Physics

Piezoelectric Effect

The generation of electric polarization charge in non-centrosymmetric crystals when subjected to mechanical stress (and vice versa).

Direct: P_i = d_ijk σ_jk; Reverse: ε_jk = d_ijk E_i C/N or m/V (Piezoelectric Coefficient d)

Condensed Matter & Materials Physics

Poisson's Ratio

The ratio of transverse lateral strain to axial longitudinal strain in a material subjected to uniaxial stress.

ν = -ε_transverse / ε_axial = -(Δd / d₀) / (ΔL / L₀) Dimensionless Ratio (-1 to 0.5)

Condensed Matter & Materials Physics

Polaron

A composite quasiparticle consisting of a conduction electron (or hole) bound together with its surrounding self-induced lattice…

m*_polaron = m* (1 + α_coupling / 6) Quasiparticle Mass

Condensed Matter & Materials Physics

Quantum Confinement Effect

The shift and quantization of electronic energy levels when charge carriers are confined within spatial dimensions smaller than their De…

E_confinement ∝ 1 / L² (When dimension L ≤ De Broglie wavelength) eV (Confinement Energy Shift)

Condensed Matter & Materials Physics

Quantum Hall Effect

A quantum mechanical version of the Hall effect observed in 2D electron gases at low temperatures and intense magnetic fields, where Hall…

R_H = h / (ν e²), ν = 1, 2, 3... Ω (Von Klitzing Constant R_K ≈ 25812.807 Ω)

Condensed Matter & Materials Physics

Reciprocal Lattice

The Fourier transform space of a real-space crystal lattice, where every point corresponds to a set of parallel lattice planes in the real…

b₁ = 2π (a₂ × a₃) / (a₁ · (a₂ × a₃)), G · R = 2π n m⁻¹ (Reciprocal Distance)

Condensed Matter & Materials Physics

Seebeck Effect

The direct conversion of a temperature gradient into an electrical voltage across a conductor or semiconductor.

V = S ΔT = S (T_hot - T_cold) μV/K (Seebeck Coefficient S)

Condensed Matter & Materials Physics

Semiconductor

A class of crystalline solids possessing electrical conductivity between that of conductors and insulators, controllable by temperature…

σ = e (n μ_e + p μ_h), n_i = √(N_c N_v) e^(-E_g / (2 k_B T)) S/m (Electrical Conductivity)