classical free electron theory.pptx

PRESENTATION
TOPIC : CLASSICAL FREE ELECTRON THEORY
SUBMITTED BY : THARANYA S
[22ECR216]

1. EXPLORING THE CLASSICAL FREE ELECTRON THEORY : AN ANALYSIS OF ITS SUCCESS, LIMITATIONS, ASSUMPTIONS S.THARANYA 22ECR216 PHYSICS FOR ELECTRONICS AND COMMUNICATION ENGINEERING

2. COMPONENTS INTRODUCTION HISTORY ASSUMPTIONS OF CFET LIMITATIONS OF CFET SUCCESS OF CFET BASIC TERMS INVOLVED IN CFET

3. INTRODUCTION Classical free electron theory is a fundamental concept in quantum mechanics. This presentation explores the assumptions, successes, and limitations of this theory. The aim is to deepen our understanding of the theory and its impact on modern physics.

4. HISTORY INTRODUCED BY P. DRUDE IN 1900 DEVELOPED BY LORENTZ  IN 1909

5. ASSUMPTIONS OF CLASSICAL FREE ELECTRON THEORY

6. LIMITATIONS OF CLASSICAL FREE ELECTRON THEORY

7. SUCCESS OF CLASSICAL FREE ELECTRON THEORY Despite its limitations, classical free electron theory has been successful in explaining some important phenomena. For example, it can explain the electrical conductivity of metals and the behavior of electrons in a magnetic field. The theory has also been used in the development of modern technologies like semiconductors and transistors.

8. BASIC TERMS INVOLVED IN CFET DRIFT VELOCITY MOBILITY MEAN FREE PATH MEAN COLLISION TIME RELAXATION TIME BAND GAP CURRENT DENSITY

9. Drift Velocity ( V d ) The drift velocity is defined as the average velocity  acquired by the free electron in particular direction,  due to the applied electric field. Mobility  The mobility is defined as the drift velocity ( V d )   acquired by the electron per unit electric field (E) Mean free path The average distance travelled by a electron between two successive collision is called mean free path.

10. Mean collision time  (or) Collision time It is the time taken by the free electron between two successive collision. Relaxation time It is the time taken by the electron to reach equilibrium position from disturbed position in the presence of electric field where  l  is the distance travelled by the electron. The value of relaxation time is of the order of 10 –14  sec.  Band gap ( E g ) Band gap is the energy difference between the minimum energy of conduction band and the maximum energy of valence band.

11. Current density (J) It is defined as the current per unit area of cross section of an imaginary plane hold normal to the direction of the flow of current in a current carrying conductor.

12. ADVENT OF QUANTUM FREE ELECTRON THEORY :  Quantum free electron theory was proposed by Sommerfeld in 1928.  It overcomes many of the drawbacks of classical theory.  Sommerfeld explained them by choosing Fermi Dirac statistics instead of Maxwell-Boltzmann statistics . He developed this theory by applying the principles of quantum mechanics. Assumptions of Quantum Free Electron Theor This Photo by Unknown author is licensed under CC BY-SA .

13. THANK YOU ! SUBMITTED BY : THARANYA S ECE – D 22ECR216