Surface state Dirac point Fermi level Bi 2 Se 3 GaAs Bi 2 Se 3 Background: During the past two years, studies involving topology have led to predictions.

Slides:



Advertisements
Similar presentations
Quasiparticle Scattering in 2-D Helical Liquid arXiv: X. Zhou, C. Fang, W.-F. Tsai, J. P. Hu.
Advertisements

TEM sequence of a single grain boundary formation, growth, rotation, sliding and migration between two Au nanoparticles. Scale bars are 10 nm. It is well.
Quantum Hall effect at with light John Cerne, SUNY at Buffalo, DMR In metals, magnetic fields deflect moving charges to produce an electric field.
Interacting charge and spin chains in high magnetic fields James S. Brooks, Florida State University, DMR [1] D. Graf et al., High Magnetic Field.
National Science Foundation Increasing thermo-electric conversion efficiency by defect engineering Robert F. Klie, University of Illinois at Chicago, DMR.
Epitaxial Graphene: a New Platform for Carbon Electronics Materials Development State of the Art Education and Diversity The GT MRSEC has been developing.
National Science Foundation Developing Oxides for Solar Energy Conversion Steven May, Drexel University, DMR Outcome: Researchers at Drexel University.
What is “Solid State Physics”??. Reminder of the Course Objective To expose students to the rich, broad, varied field of SOLID STATE PHYSICS This ISN'T.
Brillouin Light Scattering Studies of Magnetic Multilayers Cyrus Reed, Milton From Department of Physics and Astronomy, Western Washington University What.
Robustness of Topological Superconductivity in Proximity-Coupled Topological Insulator Nanoribbons Tudor D. Stanescu West Virginia University Collaborators:
PHY 042: Electricity and Magnetism Introduction Prof. Pierre-Hugues Beauchemin.
Motivation and Impact: Formation of one-dimensional nanostructures (“nanowires”) is of major importance to nanoscience, because (1) it offers the opportunity.
Materials World Network: Self-assembled Nanocomposite Magnetoelectric Thin Films Nian Sun, Northeastern University, DMR Intellectual Merit:Fig.
Carrier and Spin Dynamics in InSb- and InMnSbBased Heterostructures, Giti Khodaparast, Virginia Tech, DMR ,, The samples for this projects are provided.
When and why are ultrathin films of metallic oxides not metallic? Jiandi Zhang, Louisiana State University & Agricultural and Mechanical College, DMR
Superconducting/Semiconducting Nanowires, Nanotubes, and Ultrathin Films Wenhao Wu, Texas A&M University, DMR We use membranes with a honeycomb.
National Science Foundation Material for Future Low-Power Electronics Daniel Gall, Rensselaer Polytechnic Institute, DMR Outcome: Researchers at.
Topology is familiar mostly from mathematics, but also natural sciences have found its concepts useful. Those concepts have been used to explain several.
Strands of DNA have been used as tiny scaffolds to create superconducting nanodevices that demonstrate a new quantum interference phenomenon. These nanowire.
STRUCTURE AND MAGNETIC PROPERTIES OF ULTRA-THIN MAGNETIC LAYERS
Transition Metal Doped Sb 2 Te 3 and Bi 2 Te 3 Diluted Magnetic Semiconductors Ctirad Uher DMR By low temperature MBE technique, we were able to.
Quantum Spin Hall Effect and Topological Insulator Weisong Tu Department of Physics and Astronomy University of Tennessee Instructor: Dr. George Siopsis.
Spin Dependent Transport Properties of Magnetic Nanostructures Amédée d’Aboville, with Dr. J. Philip, Dr. S. Kang, with Dr. J. Philip, Dr. S. Kang, J.
Insert Figure 1 approximately here. Bismuth nanowires or bismuth nanotubes? -Bismuth nanowires are a vehicle for the study of size- dependent electronic.
M.T. Bell et al., Quantum Superinductor with Tunable Non-Linearity, Phys. Rev. Lett. 109, (2012). Many Josephson circuits intended for quantum computing.
Impurity sites in a semiconductor discovered through their localized vibrational signatures in the infrared Anant K. Ramdas and Sergio Rodriguez, Purdue.
FRG: M n+1 AX n Phase Solid Solutions: Unique Opportunities at Engineering Bulk and Surface Properties Micheal W. Barsoum, Drexel University, DMR
“Bottom-Up” Design of Nanostructured Conducting Polymer Thin Films Evgueni E. Nesterov, Louisiana State University & Agricultural and Mechanical College,
Dung-Hai Lee U.C. Berkeley Quantum state that never condenses Condense = develop some kind of order.
Controlling the Curie temperature in the ferromagnetic semiconductor (Ga,Mn)As through location of Fermi level in the impurity band Margaret Dobrowolska,
LaBella Group Towards an Atomic Scale Understanding of Spin Polarized Electron Transport Towards an Atomic.
Infrared Hall effect in conventional and unconventional materials John Cerne, SUNY at Buffalo, DMR In metals, magnetic fields (H) deflect moving.
A magnetically-controlled superconducting switch Norman Birge, Michigan State University, DMR The interplay between superconductivity and ferromagnetism.
Materials World Network: Understanding & controlling optical excitations in individual hybrid nanostructures Gregory J. Salamo, University of Arkansas,
A Web Laboratory for Visual Interactive Simulation of Epitaxial Growth Feng Liu University of Utah Recently, we have developed a prototype of web laboratory.
Azerbaijan National Academy of Sciences Institute of Radiation Problems New Challenges in the European Area: Young Scientist's1st International Baku Forum.
National Science Foundation GOALI: Epitaxial Growth of Perovskite Films and Heterostructures by Atomic Layer Deposition and Molecular Beam Epitaxy John.
DMR : Carrier and Spin Dynamics in InSb- and InMnSbBased Heterostructures, PI: Giti Khodaparast, Physics Department, Virginia Tech.,,  The goal.
Raman Enhancement Effect on Two-dimensional Layered Materials: Graphene, h-BN, and MoS 2 Mildred Dresselhaus, Massachusetts Institute of Technology, DMR.
Introduction to topological superconductivity and Majorana fermions
Infrared and magneto- optical studies of topological insulators Saša V. Ðorđević Department of Physics.
National Science Foundation Sb-doped SnO 2 as a transparent contact on InGaN/GaN LEDs James S. Speck, University of California-Santa Barbara, DMR
4.12 Modification of Bandstructure: Alloys and Heterostructures Since essentially all the electronic and optical properties of semiconductor devices are.
From quasi-2D metal with ferromagnetic bilayers to Mott insulator with G-type antiferromagnetic order in Ca 3 (Ru 1−x Ti x ) 2 O 7 Zhiqiang Mao, Tulane.
Doped rare-earth manganese oxides (manganites) exhibit a wide variety of physical phenomena due to complex interplay of electronic, magnetic, orbital,
Bulk Hybridization Gap and Surface Conduction in the Kondo Insulator SmB 6 Richard L. Greene, University of Maryland College Park, DMR Recently,
Advanced Optical Glasses for Novel Optical Fibers Kathleen Richardson, Clemenson University Research Goundation, DMR The international, multidisciplinary.
Magnetic Moments in Amorphous Semiconductors Frances Hellman, University of California, Berkeley, DMR This project looks at the effect of magnetic.
CAREER: Position-Controlled Doping of Semiconductor Nanocrystals Y. Charles Cao, University of Florida, DMR Doping refers to the process of intentionally.
B-1.2: Use appropriate laboratory apparatuses, technology, and techniques safely and accurately when conducting a scientific investigation.
Spin at the Nanoscale: Material Synthesis and Fundamental Physics Min Ouyang, University of Maryland – College Park, DMR In the FY08, we continued.
Topological Superconductors “Interplay of disorder and interaction in Majorana quantum wires,” Alejandro M. Lobos, Roman M. Lutchyn, and S. Das Sarma,
Dirac’s inspiration in the search for topological insulators
Single-molecule transistors: many-body physics and possible applications Douglas Natelson, Rice University, DMR (a) Transistors are semiconductor.
Partnership between NMHU and OSU in Electronic, Optical and Magnetic Materials; DMR One step synthesis of fluorescent graphene quantum dots through.
Superconductivity in CuxBi2Se3 and its Implications for the Undoped Topological Insulator Garrett Vanacore, Sean Vig, Xiaoxiao Wang, Jiang Wang, University.
北京大学量子材料科学中心 Seminar Qinglin He
Topological Insulators
What is Solid State Physics??
4-year PhD in Nanoscience
Partnership between NMHU and OSU in Electronic, Optical and Magnetic Materials; DMR One step synthesis of fluorescent graphene quantum dots through.
What is “Solid State Physics”??
Robust topological interfaces and charge transfer in epitaxial Bi2Se3/II-VI semiconductor superlattices (NanoLetters 2015) Zhiyi Chen, Lukas Zhao, Kyungwha.
Landau Quantization and Quasiparticle Interference in the
Majorana Spin Diagnostics
SOC Fermi Gas in 1D Optical Lattice —Exotic pairing states and Topological properties 中科院物理研究所 胡海平 Collaborators : Chen Cheng, Yucheng Wang, Hong-Gang.
Glass-like Thermal Conductivity in Epitaxial Oxygen-Vacancy-Ordered Oxide Films UMN MRSEC Award DMR# Xiaojia Wang (IRG-2) & Chris Leighton.
Simple Stretch “Flips” the Sign of Charge Carriers
Observation of Majorana fermions in a ferromagnetic chains on a superconductor Princeton Center for Complex Materials (DMR ) Stevan Nadj-Perge,
Introduction to topological superconductivity and Majorana fermions
Presentation transcript:

Surface state Dirac point Fermi level Bi 2 Se 3 GaAs Bi 2 Se 3 Background: During the past two years, studies involving topology have led to predictions of entirely new quantum states of matter, such as charge carriers with zero mass and new quantum quasiparticles known as Majorana fermions. Since these novel concepts emerge from topological properties of a solid, they can be designed and manipulated by controlling the surface of a solid or by designing the interfaces within a multilayer structure. Molecular beam epitaxy (MBE) is ideally suited to achieve these goals. Description of achievement and methodology: Our team has focused on two approaches, both involving the manipulation of topological effects by MBE: on creating entirely new materials with topological properties that are protected by time reversal symmetry (topological insulators, TIs); and on forming new combinations of traditional materials, in which the interfaces between these materials results in entirely new effects (in our case, in the formation of new quasiparticles referred to as Majorana fermions). Topological insulators: We have successfully grown high-quality specimens of the canonical topological insulators Bi 2 Se 3 and Bi 2 Te 3. The crystalline graphite-like structure of this system is shown in the transmission electron micrograph (a) on the right. The existence of the so-called Dirac cone is demonstrated by the angle-resolved photo- emission image (b), attesting to the existence of massless electrons, which have their spin locked at right-angle to their momentum (spin-momentum locking). Majorana fermions: By interfacing MBE-grown nanolayers of narrow-gap semiconductor InSb with a superconducting Nb nanowire shown in Fig. (c), we have also succeeded in observing clear signatures of Majorana fermions, elusive quasiparticles which could be used as building blocks of topological quantum computers. This Majorana fermion signature comes in the form of a discontinuity in the progression of Shapiro steps in the Josephson effect shown by the oval in Fig. (d) in the presence of a moderately strong magnetic field. (a) (b) (c) (d) Margaret Dobrowolska, University of Notre Dame, DMR

: DMR : Electron spin Effects in Semiconductor Nanostructures Margaret Dobrowolska, University of Notre Dame, DMR Education: Our program typically involves three graduate students and two undergraduate students each year. These students tare exposed to a wide range of materials fabrication and characterization techniques, thus preparing them for the US manpower needs in the area of semiconductor science and technology. We also conduct a broad program of international scientific exchanges. Currently we are hosting Prof. Sanghoon Lee from Korea University on his sabbatical. Moreover, Dr. K. Dziatkowski of Warsaw University and Prof. T. Wojtowicz of the Polish Academy of Sciences will be our guests on extended visits to conduct research in our group. Societal Impact: Our group has continually acted as a resource of materials for other groups. We are currently interacting with at least 15 other institutions around the world by providing them with magnetic semiconductor specimens for their research; and at least ten graduate students in institutions other than Notre Dame are currently doing their doctoral research on materials which we have provided. The understanding of these materials obtained in our laboratory is thus automatically of benefit to our collaborators, whose research depends not only on the specimens that we provide, but on the intellectual input from our group in the form of characterization and general understanding of the properties of these materials.