Condensed Matter & Materials Physics — 60 Terms Defined

Shape Memory Alloys Condensed Matter & Materials Physics % (Recoverable Superelastic Strain) A class of smart metallic alloys that can be deformed when cold, but return to their original pre-deformed shape when heated above a transition temperature. Reversible Austenite (High T) ↔ Martensite (Low T) Phase Shift

Spin Glass Condensed Matter & Materials Physics Disordered Magnetic Phase A disordered magnetic state characterized by random, competing ferromagnetic and antiferromagnetic interactions that freeze atomic spins into a frustrated, non-periodic spatial orientation. Frustrated Exchange Interaction J_ij

Superalloys Condensed Matter & Materials Physics High Temperature Strength (MPa at >800 °C) High-performance metallic alloys engineered to maintain exceptional mechanical strength, creep resistance, and oxidation resistance at high operational temperatures. γ' Phase Precipitation: Ni₃(Al, Ti)

Superconductivity Condensed Matter & Materials Physics K (Critical Temperature T_c) A macroscopic quantum state of matter where certain materials exhibit exactly zero electrical DC resistance and complete expulsion of magnetic fields below a critical temperature T_c. R = 0 (for T < T_c), B = 0 (Meissner expulsion)

Superfluidity Condensed Matter & Materials Physics K (Lambda Transition Temperature) A macroscopic quantum state of matter where a fluid flows with exactly zero viscosity and zero kinetic entropy. Viscosity η = 0 (Below Lambda point T_λ = 2.17 K)

Surface Energy Condensed Matter & Materials Physics J/m² or N/m The excess thermodynamic energy at the surface of a material relative to its interior bulk, caused by disrupted, incomplete atomic bonds. γ = dW / dA

Topological Insulator Condensed Matter & Materials Physics Quantum Phase Class A quantum material that behaves as an electrical insulator in its 3D interior bulk but features robust conducting metallic states on its 2D surface boundary. Z₂ Topological Invariant ν = 1

Type I & II Superconductors Condensed Matter & Materials Physics T or A/m (Critical Magnetic Field) The classification of superconductors based on their magnetic field response and flux penetration characteristics. Type I: Single H_c; Type II: Lower H_c1 and Upper H_c2

Unit Cell Condensed Matter & Materials Physics Å³ or nm³ (Unit Cell Volume) The smallest repeating structural unit of a crystal lattice that generates the entire 3D crystal structure through simple translational repetition. V_cell = a · (b × c)

Valence Band Condensed Matter & Materials Physics eV (Energy Levels) The highest range of electron energy bands in a solid that is fully occupied by bound valence electrons at absolute zero temperature. Occupied by valence electrons at T = 0 K

Work Hardening Condensed Matter & Materials Physics MPa (Increased Yield Strength) The strengthening of a metal by plastic deformation, caused by dislocation multiplication and entanglement obstructing further slip. σ_y = σ₀ + α G b √ρ_dislocation (Taylor Relation)

Young's Modulus Condensed Matter & Materials Physics Pa or GPa (Gigapascals) A mechanical property measuring the tensile or compressive stiffness of a solid material in its linear elastic deformation regime. E = σ / ε = (F / A) / (ΔL / L₀)