Condensed Matter Physics

Condensed Matter Physics

• Studies the macroscopic and microscopic physical properties of matter, involving a large number of interacting constituents (atoms or molecules).
• Deals with properties of matter at ordinary chemical and thermal energy scales.
• Has the largest number of direct practical applications and is intellectually vital.

Crystals

• Solid materials with a highly ordered, repeating pattern called a crystal lattice.
• Characteristic shape and structure are due to this orderly arrangement.
• Types of bonding:
  • Ionic Bonding: occurs when electrons are transferred from one atom to another, resulting in positively charged ions (cations) and negatively charged ions (anions).
• Bragg's Law: describes the diffraction of x-rays by crystals, relating to the wavelength of the incident x-ray, distance between crystal planes, and angle of incidence.

Semiconductors

• The Current-Voltage Relationship for a Diode (Shockley Diode Equation) models the exponential relationship between the diode current and voltage across the diode.
• Equation: 𝐼 = 𝐼0 (𝑒 𝑛𝑉𝑇 – 1)
• Where: I is the diode current, I0 is the reverse saturation current, V is the voltage across the diode terminals, n is the ideality factor, and VT is the thermal voltage.

History of Condensed Matter

• Humphry Davy (Early 19th Century): challenged John Dalton's atomic theory, observing metallic properties in chemical elements, and suggested that atoms had inner structures.
• Michael Faraday (1823): successfully liquefied gases, including chlorine, expanding our understanding of the behavior of matter under extreme conditions.

Laboratory Activity: Investigating Thermal Conductivity in Condensed Matter

• Objective: to explore the thermal conductivity of various condensed matter materials and understand its implications in practical applications.
• Materials needed: metal spoon, ceramic mug, plastic container, heat source, stopwatch or timer, thermometer, and ruler.
• Procedure:
  • Measure dimensions of each material and record initial temperatures.
  • Heat one end of each material uniformly using a heat source.
  • Record time taken for temperature to increase by a predetermined amount (ΔT) at 20°C.
  • Repeat the experiment for each material to ensure reliability and precision.
  • Calculate the rate of temperature increase and compare thermal conductivities of different materials based on calculated rates.