Teaching

• Solid State Physics (PH523) – M.Sc. core course

Credit (3–1–0–8) Pre-requisites: Nil

Contents:

Crystal physics: Symmetry operations; Bravais lattices; Point and space groups; Miller indices and reciprocal lattice; Structure determination; diffraction; X-ray, electron and neutron; Crystal binding; Defects in crystals; Point and line defects.

Lattice vibration and thermal properties: Einstein and Debye models; continuous solid; linear lattice; acoustic and optical modes; dispersion relation; attenuation; density of states; phonons and quantization; Brillouin zones; thermal conductivity of metals and insulators.

Electronic & Magnetic properties: Free electron theory of metals; electrons in a periodic potential; Bloch equation; Kronig-Penny model; band theory; Semiconductor physics; Quantum Hall effect. Dielectric Response. Magnetic properties.

Superconductivity: General properties of superconductors, Meissner effect; London equations; coherence length; type-I and type-II superconductors.

Noncrystalline Solids: Glasses, Amorphous ferromagnets, Amorphous Semiconductors.

Quasicrystals: Stable quasicrystal, metastable quasicrystal.

Textbooks:

C. Kittel, Introduction to Solid State Physics, Wiley India (2009). M. A. Omar, Elementary Solid State Physics, Addison-Wesley (2009).

• Measurement Techniques (PH527) – M.Sc. core course

Credit  (2–0–2–6) Pre-requisites: Nil

Contents

Basics of measurement: uncertainty in measurements, Comparison of measured & accepted values and Two measured values, Checking relationships with a graph, Fractional uncertainties, multiplying two measured numbers, Propagation of uncertainties;

Low level DC measurement of voltage, current and resistance, C-V and Impedance spectroscopy; Deep Level Transient Spectroscopy, Hall effect and Time of Flight methods for charge carriers; Magnetic Response using SQUID magnetometer and VSM;

UV-VIS-NIR spectro-photometer & Ellipsometry, FTIR, Raman spectroscopy; Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Scanning Tunneling Microscopy (STM), Atomic Force Microscopy (AFM); X-ray diffraction (XRD) and grazing angle XRD;

Textbooks:

John R. Taylor, An Introduction to Error Analysis, (University Science Books, 2nd Edition, 1997). Milton Ohring, Materials Science of Thin Films, (Academic Press, 2nd Edition,2006).

A list of courses taught  with course titles, level (UG/PG) and number of times taught:

Course Objectives                                                         

The objective of this course is to present a unified discussion on the fundamentals of atomic force microscopy and scanning tunneling microscopy. The course covers instrumental aspects and summarizes the basics of the tip-sample interaction and contact mechanics. In addition, this course introduces probe based physical property measurement of materials with nanoscale resolution.

Learning Outcomes

Upon completion of this course, the student should:

1. Understand the concepts of quantum tunneling and its application in imaging and manipulation at the surface with atomic resolution.
2. Understand the basic aspects of tip-surface interactions in contact and non-contact regimes.
3. Be able to describe the basic components necessary to build a simple AFM / STM instruments.
4. Have confidence in exploring the technique beyond imaging for device applications like memristors, organic electronics and spintronics.

Course Contents

Unit I: Tip-Surface Interaction                                                                    

Non-contact regime Intra-molecular Interactions, Electric Dipoles, Inter-molecular interactions: Physical models, ion-dipoles, Keesom forces, Dispersion Force

Contact regime Hamaker theory, surface energies, Dejaugin approximation, contact mechanics, Hertz model, JKR model, DMT model.

Unit II:  Atomic Force Microscope (AFM)                                                     

AFM components, AFM calibration, analysis of AFM images in each mode.

Force Spectroscopy Cantilever mechanics, Approach-retract curves, Processing Force curves, Modulus and adhesion Maps, Lateral Force Microscopy, Conducting Atomic Force Microscopy, Nanoindentation.                                                         

Dynamic AFM frequency response, conservative and dissipative interaction forces, excited probe interacting with sample (linear theory), Amplitude and Frequency modulation,  Attractive and Repulsive Regimes and Phase Contrast Modualtion AFM.

Unit III:  Scanning Tunneling Microscope (STM)                                                         

Quantum tunneling, WKB approximation for field emission, STM instruments and its components, Scanning tunneling spectroscopy, Inelastic electron tunneling spectroscopy, STM image analysis.

Unit IV: Special SPM techniques                       

Scanning non-linear dielectric microscopy (SNDM), scanning near field optical microscopy (SNOM), atomic and molecular manipulations, AFM-based lithography, spin-polarized STM, industrial applications of AFM, memristive applications, organic electronics and spintronics.

Course Contents

Unit I: Forces, energies and time scales in soft matter                                                           

Thermodynamic and statistical aspects of intermolecular forces, Boltzmann distribution and chemical potential,  pair potential, strong intermolecular forces – covalent and Coulomb interactions, Van der Waals forces, steric forces, hydrogen bonding, response of matter to a shear stress, viscoelastic behavior, relaxation time.

Unit II:  Molecular order in soft matter                                   

Phase transitions, order parameter, liquid crystallinity – nematic, cholesteric, smectic, columnar; colloids and gels, crystallinity in polymeric materials, weight dispersion in polymers, random walk models, dimensions of polymer chains,  persistence length of flexible chains, radius of gyration, Flory-Huggins theory.

Unit III:  Soft matter in nature             

Supramolecular self-assembly, aggregation in amphiphilic molecules, soluble and insoluble monolayers, critical micellar concentration,  effect of dimensionality and geometry, spherical and cylindrical micelles, bilayers and vesicles,  biological lipid membranes, nucleic acids and proteins, surfactants, soaps and emulsions, technological applications of soft matter.