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FRONTIERS IN PHYSICS: Lecture 1 The Nanoworld – Where Size is Everything... Philip Moriarty, B403 School of Physics & Astronomy

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Presentation on theme: "FRONTIERS IN PHYSICS: Lecture 1 The Nanoworld – Where Size is Everything... Philip Moriarty, B403 School of Physics & Astronomy"— Presentation transcript:

1 FRONTIERS IN PHYSICS: Lecture 1 The Nanoworld – Where Size is Everything... Philip Moriarty, B403 School of Physics & Astronomy Just what is nanoscience? Manipulating atoms, molecules, and electrons Frontiers in Physics – module overview, structure, and assessment An artificial periodic table OUTLINE

2 FRONTIERS IN PHYSICS – An Overview The Frontiers in Physics module has been designed to: (i)Introduce you to the option strands in the School’s physics courses and, perhaps more importantly, (ii)Give you an insight into some of the key cutting edge areas of 21 st century physics and astronomy. Interwoven themes (but not restricted to these) 2. Astronomy Lecturer: Frazer Pearce, B103, Centre for Astronomy and Particle Theory 3. Medical Physics Lecturer: Richard Bowtell, MR13 (Magnetic Resonance Centre) and C Nanoscience Lecturer: Philip Moriarty, B403, Please me to organise an appointment.

3 FRONTIERS IN PHYSICS – An Overview

4 Website FRONTIERS IN PHYSICS – An Overview Moodle + + Wordpress (To be announced…soon…I promise). There isn’t a dedicated textbook to cover the Frontiers material. (This is largely because one of our aims is to introduce you to exciting new “off the press” science). e-book in preparation for Nano component of module. Sets of lecture notes availble via Moodle. Powerpoint slides also available. We will, however, refer you to the relevant sections in Knight and, equally importantly, give references to websites and to books in the library. Use the library! Textbook

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6 Assessment 20% coursework; 80% examination Coursework (CW) sets for Semester 1 CW Set 3 – 16 Oct. (Hand-in: 23 Oct.) CW Set 5 – 30 Oct. (Hand-in: 06 Nov.) CW Set 7 – 13 Nov. (20 Nov.) CW Set 9 – 27 Nov. (04 Dec.) 500 word scientific article (after Christmas holiday – hand in on Jan. 24) Exam: standard first year format. Four questions from six. Each question worth 25 marks. If you answer more than four questions, all will be marked and the best four marks taken.

7 Exam paper “walk-throughs”

8 Watching videos is not education. The learner needs to do at least as much work as the teacher to grasp the concepts. My job in these lectures is primarily to enthuse you and get you interested in the material. A lot of your learning will happen outside of B1. Rant of the day perish-guilty-confessions-of-a-youtube-physicist/

9 Peer Instruction Will try Mazur’s Peer Instruction scheme in some Frontiers lectures…

10 Just what is nanoscience? Let’s first consider the nanometre unit. A useful “pop. science” estimate is that 1 nm is ~ the length the average person’s hair grows in one second. It is, of course, m but what does this represent in terms of physical quantities and structures with which you’re more familiar?

11 Which of the following is closest to the wavelength of red light? A.0.6 nm B.6 nm C.60 nm D.600 nm E.6,000 nm

12 Which of the following is closest to the size of a human red blood cell? A.50,000 nm B.5000 nm C.50 nm D.5 nm E.0.5 nm

13 The diameter of a gold atom is approximately: A.3 nm B.0.3 nm C.0.03 nm D nm

14 The wavelength of an electron (mass = kg) travelling at 10 6 ms -1 is approximately: A.0.01 nm B.0.6 nm C.20 nm D.300 nm E.2112 nm

15 Just what is nanoscience? Sometimes nanoscience is defined as the study of phenomena, structures, and materials “at the nanometre level” This is a nebulous/ “woolly” definition. Wikipedia, for example, states “Generally nanotechnology deals with structures 100 nanometers or smaller, and involves developing materials or devices within that size.” [Aside: Be careful when quoting Wikipedia – use additional sources to check Wikipedia’s statements]. Admission: I’ve also been guilty of using this type of definition in the past! But why 100 nm? Why not 110 nm or 512 nm or 5 nm...?

16 Just what is nanoscience?: Size-dependent properties Much better to focus on modification of properties than on arbitrary size limits. Cross-over from microscopic to nanoscopic regime can be ill-defined (depends on the system). Good “rule of thumb”: An optical microscope cannot resolve the detail of nanoscale structures, devices, or systems. The key concept behind much of nanoscience is that simply by changing the size of an object, we change its physical, chemical (and biological) properties.

17 An artificial periodic table: designer materials Instead of building materials from different elements, control properties by changing size/shape of nanoparticles...

18 “A nugget of purest green...” But gold isn’t always coloured gold... Au nanoparticles (diameter 2 – 10 nm) are red in colour Simply by changing nanoparticle size (for certain materials), entire visible spectrum can be covered. From Blackadder II, Episode 4 – “Money” © BBC (1986) sitemason.vanderbilt.edu/files/ioOfKM/cdse4.jpg

19 Reaching the atomic limit... How far can we take this? Can we manipulate matter at the atomic level? Images from Eigler et al., IBM Almaden; IBM Zurich; and Stefan Tautz, International University Bremen. Use scanning probe microscopes (Lectures 4 and 5) to control not only individual atoms but single bonds.

20 Flipping atomic dominoes

21 But I am not afraid to consider the final question as to whether, ultimately--- in the great future---we can arrange the atoms the way we want; the very atoms, all the way down! RP Feynman, “There’s Plenty of Room at the Bottom”, 1959 The origin of nanotech.

22 How many atoms are there in 1 cm 3 of a solid? 1.~ ~ ~ ~ 10 40

23 But I am not afraid to consider the final question as to whether, ultimately--- in the great future---we can arrange the atoms the way we want; the very atoms, all the way down! RP Feynman, “There’s Plenty of Room at the Bottom”, 1959 The origin of nanotech. Let’s say atoms are spaced by 4 Å (=0.4 nm). [This can be measured directly using X-ray diffraction or – as we’ll see – a scanning tunnelling microscope]

24 Why is nanotech. so important? 0.4 nm In the solid, there is 1 atom per 0.4 x 0.4 x 0.4 nm 3 So, 1 atom per nm 3  There are 1/0.064 atoms per nm 3 This is, on average, ~ 16 atoms per nm 3

25 How many nm 3 in 1 cm 3 ?

26 Why is nanotech. so important? 0.4 nm In the solid, there is 1 atom per 0.4 x 0.4 x 0.4 nm 3 So, 1 atom per nm 3  There are 1/0.064 atoms per nm 3 This is, on average, ~ 16 atoms per nm 3 How many nm 3 in 1 cm 3 ?? 10 7 x 10 7 x 10 7 =  1 cm 3 = nm 3 There are approximately atoms in 1 cm 3 of a solid.

27 Number of stars in observable universe? Estimates vary but ~ seems to be reasonably well accepted at present. Number of atoms in your body is a million times greater than the number of stars in the (observable) universe!

28 Why is nanotech. so important? So, there are approximately atoms in 1 cm 3 of a solid. Imagine that each atom represents a bit of information (a ‘1’ or a ‘0’).  We have, in principle, the ability to store bits of information in 1 cm 3. ~ GB ( = 10 6 Petabytes) in 1 cm 3. Using nanotechnology, we have the potential ability to store all the data in ~ 8,000,000, GB iPads in 1 cm 3. So what?!

29 /schmidt-data/


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