A lap 2019. május 17., 16:09-kori változata

Fundamentals of Nanophysics

Course Information

• Lecturers: András Halbritter, Szabolcs Csonka, Peter Makk
• Responsible lecturer: András Halbritter
• Language (2019): English
• Schedule: 3 lectures/week, on Wednesday, 9:30-12:00
• Neptun Code: BMETE11MF37
• Credits: 4
• Exam: The grade is based on an oral exam in the exam period. At the exam the printed out lecture notes can be used, the emphasis is put on the level of understanding.

Syllabus

The building blocks of nowadays electronic devices have already reached a few tens on nanometers sizes, and further miniaturization requires the introduction of novel technologies. At such small length-scales the coherent behavior and the interaction of electrons, together with the atomic granularity of matter induce several striking phenomena, that are not observed at the macroscopic scale. The course gives an introduction to a broad set of nanoscale phenomena following the topics bellow:

• Introduction, characteristic length-scales, nanowires, interference phenomena (2019). Characteristic length-scales, two dimensional electron gas systems, nanoscale fabrication and imaging techniques. Diffusive and ballistic nanowires, quantum wires, Landauer description of mesoscopic transport, conductance quantization. Four probe resistance in a quantum wire. Coherent and incoherent serial connection of scattering centers. Mesoscopic Aharonov-Bohm effect, Altshuler-Aronov-Spivak oscillations. Decoherence due to the interaction with the environment. Conductane fluctuations and weak localization.

• Mesoscopic phenomena in atomic and molecular nanojunctions (2019). Experimental techniques to create atomic-sized metallic junctions and single-molecule nanowires. Uncovering the mesoscopic PIN code of single-atom and single-molecule contacts: conductance fluctuation analysis, shot noise measurements and superconducting subgap spectroscopy. Vibrationaly spectroscopy. Conductance through single organic molecules: resonant tunneling model, conductance as a function of molecular length (coherent and incoherent transport), conformation dependent conductance, role of the anchoring group, quantum interference, thermopower measurements revealing HOMO/LUMO conductance, inelastic electron tunneling spectroscopy.

• Quantized Hall effect (2019). Classical Hall effect. Landau levels. Integer Quantum Hall effect. Edge states. Role of electron spin. Role of disorder.

• Noise as the signal (2019). Definition of noise: spectral density of noise and current-current correlation function. Shot noise in a single channel quantumwire. Shot noise thermometry. Uncovering the transmission eigenvalues from noise measurements. 1/3 supression of shot noise in diffusive nanowires. Noise in the hot electron regime. Measuring the charge of the carriers: Cooper pairs and composite fermions. Shot noise in chaotic systems: classical and quantum chaos. Beam splitter experiments: two electron interference and Hanbury Brown & Twiss experiments with electrons.

• Graphene nanostructures (2019). Production methods. Band structure, massless fermions. Dirac-like spectrum, isospin, pseudospin. Klein tunneling, Barry's phase. Half integer quantum Hall effect. Mobility in graphene. Bilayer graphene. Quantum Point contacts in graphene bilayers.

• 2D Materials (2019). Van der Waals engineering, 2D materials beyond graphene. Graphene/hBN Moiré structures. Tunneling devices, electron drag phenomenon. Transition metal dichalcogenides. Quantum spin Hall phenomena, topological insulators. Magnetic and superconducting materials.

• Quantum dots (2019). Energy scales. Fabrication of quantum dots. Electrostatic model, Coulomb-blockade, Coulomb-diamond pattern. Artificial atoms, Hund's rule. Pauli-blockade. Cotunneling processes. Kondo-effect. Single electron transistor. Electron pump. Scanning SET. Spin Qubit basics.

Literature

• S. Datta: Electronic Transport in Mesoscopic Systems, Cambridge University Press, 1997.
• T. Ihn: Semiconducting nanosctructures, Oxford University Press, 2010.
• Y.V. Nazarov, Y.M. Blanter: Quantum Transport: Introduction to Nanoscience, Cambridge University Press, 2009.
• Nanofizika tudásbázis