2015 International Workshop on Emerging Functional Electronic Materials and Devices
WELCOME TO EEMD 2015
EEMD2015 is jointly organized by the annual “International Workshop on Emerging Electronic Materials and Devices” and the annual “International Workshop on Nanomaterials and Nanodevices”. EEMD2015 aims at scholarly exchange of information on recent progresses in functional materials and their applications to emerging devices, and at fostering research collaborations.
The week-long EEMD2015 Workshop has two parts: a 3-day conference and a 4-day hands-on training. The conference is from June 30 to July 2, with internationally renowned speakers presenting latest and exciting work. The topics of the conference cover experiment, theory and modeling. The second part of EEMD2015 is a 4-day hands-on training session, July 3 to July 6. The goal of the hands-on session is to help young researchers and students to improve basic research skills by using most advanced modeling techniques and softwares in density functional theory (DFT) for materials modeling and nonequilibrium Green’s function (NEGF) based DFT for quantum transport modeling. The hands-on session will also briefly cover theoretical backgrounds of both DFT and NEGF-DFT, and discuss interesting directions for solving emerging problems in materials and devices.
Wish you a wonderful trip in Beijing!
COMMITTEES
Conference Chairpersons
Hongjun Gao vice director of the IOP and the UCAS, China
Hong Guo McGill University, Canada
Scientific advisory committee
Sokrates T. Pantelides Vanderbilt University, USA
Min Ouyang Maryland University, USA
Werner Hofer Newcastle University, UK
Shouheng Sun Brown University, USA
Organizing and Program committee
Wengang Lu IOP, CAS
Yeliang Wang IOP, CAS
Hongjun Xiao IOP, CAS
Haiming Guo IOP, CAS
Yalan Feng IOP, CAS
Wei Ji Renmin University
Scientific Program
June 30, 2015. M234, IOP, CAS8:30-10:00 / Session 1
Chair: Werner Hofer
8:30-8:40 / Opening speeches
Prof. Hongjun Gao (vice director of IOP , UCAS)
Prof. Hong Guo (McGill University, Canada)
8:40-9:30 / Andrea C. Ferrari (University of Cambridge, UK)
“Advances in Raman Spectroscopy of Graphene and Layered Materials”
9:30-9:45 / Photo at the front door of Building M, IOP.
9:45-10:00 / Coffee Break
10:00-13:30 / Session 2
Chair: Siu Wai Chan
10:00-10:50 / Andreas Heinrich (Almaden Research Center, IBM, USA)
“The Quantum Properties of Magnetic Atoms on Surfaces”
10:50-11:40 / Ludwig Bartels (University of California, USA)
“Transition Metal Dichalcogenides: Growth, Characterization and Modification”
11:40-12:10 / Wenjie Liang (Institute of Physics, CAS, China)
“Transport Through 1-Dimension Nanostructures”
12:10-13:30 / Lunch time (2nd floor of the IOP Canteen)
13:30-15:30 / Session 3
Chair: Jiandi Zhang
13:30-14:20 / Werner Hofer (Newcastle University, UK)
TBD
14:20-15:10 / Yu –Hui Tang (National Central University, Jhong-Li)
“Spin Torque Effect in Spin-Filter Based Magnetic Tunnel Junction”
15:30- / Departure from the IOP to UCAS.
ONLY No. 1 bus takes a roundabout way to the Jada Palace Hotel to get luggage. Participants who live there may check your luggage at the hotel registration desk when you check out that morning. Other participants must take your luggage to the conference hall. For safety, we will lock the luggage in a separate room until all the talks of the day have finished.
18:30 / Banquet
July 1, 2015. International Center, UCAS
8:00-10:00 / Session 1
Chair: Peter Varga
8:00-8:50 / Sokrates T. Pantelides (Vanderbilt University, USA)
“Things Strange and Wonderful at the Nanoscale”
8:50-9:40 / Thomas Jung (Paul Scherrer Institute, Switzerland)
“Supramolecular Materials for Future Devices: Investigating Structure, Electron and Spin States”
9:40-10:00 / Coffee break
10:00-11:40 / Session 2
Chair: Zheng Gai
10:00-10:50 / Shouheng Sun (Brown University, USA)
“Synthesis and Assembly of Nanoparticle Catalysts for Efficient Electrochemical Reduction Reactions”
10:50-11:40 / Christian Teichert (Montanuniversität Leoben, Austria)
“Growth of Small Organic Molecules on a Variety of Graphene Substrates”
12:00-14:00 / Lunch time & Rest
14:00-16:00 / Session 3
Chair: Zhigang Shuai
14:00-14:50 / Min Ouyang (University of Maryland, USA)
“Quantum Spin Control by Light”
14:50-15:40 / Xudong Xiao (Chinese University of Hongkong, China)
“Copper-Based Chalcogenide Compound Semiconductors for Photovoltaic Applications”
15:40-16:00 / Coffee break
16:00-17:40 / Session 4
Chair: Jing Tao
16:00-16:50 / Zhigang Shuai (Tsinghua University, China)
“Modeling Electron-Phonon Couplings in Organic Thermoelectric Materials”
16:50-17:40 / Xiaogang Peng (Zhejiang University, China)
“Control of Photo- and Electro-Generated Excited States of Colloidal Quantum Dots”
18:00-19:00 / Dinner time
19:00-22:00 / Poster Session
July 2, 2015. International Center, UCAS
8:00-10:00 / Session 1
Chair: Christian A. Bobisch
8:00-8:50 / Chonglin Chen (University of Texas, San Antonio, USA)
“Interface Mechanical Strain Driven Atomic Layer-by-Layer Oxygen Vacancy Exchange Diffusion”
8:50-9:40 / Peter Varga (Vienna University of Technology, Austria)
“Ion-Beam Induced Magnetic Nanostructures”
9:40-10:00 / Coffee break
10:00-11:40 / Session 2
Chair: Xudong Xiao
10:00-10:50 / Vladimir Fal’ko (University of Manchester, UK)
“Bright, Dark and Semi-dark Excitons and Trions in Transition Metal Dichalcogenides”
10:50-11:40 / Thomas Greber (University of Zurich, Switzerland)
“Lateral Segregation on the Nanometer Scale”
12:00-14:00 / Lunch time & Rest
14:00-15:40 / Session 3
Chair: Karl-Heinz Ernst
14:00-14:50 / Xiaolong Yang (Kunshan New Flat Panel Display Technology Center, China)
“Technology Developments and Challenges in Flexible AMOLED Display”
14:50-15:20 / Yeliang Wang (Institute of Physics, CAS, China)
“Epitaxial 2D Materials: Silicene, Germanene, Hafnene and PtSe2”
15:20-15:40 / Coffee break
15:40-17:30 / Session 4
Chair: Chonglin Chen
15:40-16:10 / Jianjun Zhang (Institute of Physics, CAS, China)
“Shedding Light on SiGe Nanostructures”
16:10-16:40 / Wende Xiao (Institute of Physics, CAS, China)
“Controlling the Structural and Spin Properties of Magnetic Metal-Phthalocyanines on Au(111)”
16:40-17:10 / Yunfei Du (National Supercomputing Center in Guangzhou)
“Scaling Applications from Six application Domains on Tianhe-2”
17:10-17:30 / Best Poster Awards & Closing Speech: Prof. Sokrates T. Pantelides
18:00- / Dinner time
Abstract
Advances in Raman Spectroscopy of Graphene
and Layered Materials
Andrea C. Ferrari
Cambridge Graphene Centre, University of Cambridge, Cambridge, CB3 OFA, UK
Raman spectroscopy is an integral part of graphene research [1]. It is used to
determine the number and orientation of layers, the quality and types of edges, and the effects of perturbations, such as electric and magnetic fields, strain, doping, disorder and functional groups[2,3]. I will review the state of the art, future directions and open questions in Raman spectroscopy of graphene and related materials, focussing on the effect of disorder[3,4], doping[5,6] and deep UV laser excitation[7]. I will then consider
the shear [8] and layer breathing modes(LBMs)[9], due to relative motions of the plane, either perpendicular or parallel to their normal. These modes are present in all layered materials[10,11]. Their detection allows one to directly probe the interlayer interactios
[10,11]. They can also be used to determine the elastic constants associated with these displacements: the shear and out-of-plane elastic moduli[12]. This paves the way to the use of Raman spectroscopy to uncover the interface coupling of two-dimensional hybrids and heterostructures[10-12].
References:
1. A. C. Ferrari et al. Phys. Rev. Lett. 97, 187401 (2006)
2. A.C. Ferrari, D.M. Basko, Nature Nano. 8, 235 (2013)
3. A.C. Ferrari, J Robertson, Phys. Rev. B 61, 14095 (2000)
4. G. Cancado et al. Nano Lett. 11, 3190 (2011)
5. M. Bruna et al. ACS Nano 8, 7432 (2014)
6. A. Das et al. Nat. Nanotechnol. 3, 210 (2008)
7. A.C. Ferrari, S. Milana, P. H. Tan, D. M. Basko, P. Venezuela, submitted (2015)
8. P. H. Tan et al. Nature Materials 11, 294 (2012)
9. X. Zhang et al. Phys. Rev. B 87, 115413 (2013)
10. J. B. Wu et al. Nature Comms 5, 5309 (2014)
11. J.B. Wu et al. arXiv:1505.00095 (2015)
12. S. Milana et al. submitted (2015)
The Quantum Properties of Magnetic Atoms on Surfaces
Andreas Joachim Heinrich
Almaden Research Center, IBM, USA
The scanning tunneling microscope is an amazing experimental tool because of its atomic-scale spatial resolution. This can be combined with the use of low temperatures, culminating in precise atom manipulation and spectroscopy with microvolt energy resolution. In this talk I will apply these techniques to the investigation of the quantum spin properties of transition metal atoms on surfaces. I will highlight the interesting similarities and differences of those systems with the corresponding gas-phase atoms.
Transition Metal Dichalcogenides: Growth, Characterization and Modification
Ludwig Bartels
University of California at Riverside
I will present the growth of transition metal dichalcogenides films (MoS2, MoSe2, WS2, WSe2, MoTe2) and their alloys via chemical vapor deposition and high vacuum techniques.4 Local optical spectroscopy in conjunction with photoelectron spectroscopy shed light on the materials’ native electronic properties and their variation in the presence of contacts.1, 2 Post-growth processing allows chalcogen exchange towards local change of bandgap.3 Deposition onto functional substrates such as ferroelectrics permits further local modification of the material properties toward device applications.5
References:
1V. Klee, E. Preciado, D. Barroso, A. E. Nguyen, C. Lee, K. J. Erickson, M. Triplett, B. Davis, I. H. Lu, S. Bobek, J. McKinley, J. P. Martinez, J. Mann, A. A. Talin, L. Bartels, and F. Leonard, 'Superlinear Composition-Dependent Photocurrent in Cvd-Grown Monolayer Mos2(1-X)Se2x Alloy Devices', Nano Letters, 15 (2015), 2612-19.
2D. Le, A. Barinov, E. Preciado, M. Isarraraz, I. Tanabe, T. Komesu, C. Troha, L. Bartels, T. S. Rahman, and P. A. Dowben, 'Spin-Orbit Coupling in the Band Structure of Monolayer Wse2', J Phys Condens Matter, 27 (2015), 182201.
3Q. ma, M. Isarraraz, C wang, E. Preciado, V. Klee, S. Bobek, K. Yamaguchi, E. li, P. M. Odenthal, A. nguyen, D. Barroso, D. Sun, G. V. Palacio, M. Gomez, A. nguyen, D. Le, G Pawin, J. mann, T. F. Heinz, T. Rahman, and L Bartels, 'Postgrowth Tuning of the Bandgap of Single-Layer Molybdenum Disulfide Films by Sulfur/Selenium Exchange', Acs Nano, 8 (2014), 4672-77.
4J. Mann, Q. Ma, P. M. Odenthal, M. Isarraraz, D. Le, E. Preciado, D. Barroso, K. Yamaguchi, G. V. Palacio, A. Nguyen, T. Tran, M. Wurch, A. Nguyen, V. Klee, S. Bobek, D. Z. Sun, T. F. Heinz, T. S. Rahman, R. Kawakami, and L. Bartels, '2-Dimensional Transition Metal Dichalcogenides with Tunable Direct Band Gaps: Mos2(1-X)Se2x Monolayers', Advanced Materials, 26 (2014), 1399-404.
5A. Nguyen, P. Sharma, T. Scott, E. Preciado, V. Klee, D. Sun, I. H. Lu, D. Barroso, S. Kim, V. Y. Shur, A. R. Akhmatkhanov, A. Gruverman, L. Bartels, and P. A. Dowben, 'Toward Ferroelectric Control of Monolayer Mos2', Nano Lett, 15 (2015), DOI: 10.1021/acs.nanolett.5b00687.
Transport through 1-dimension Nanostructures
Wenjie Liang, Wengang Lv, Yuchun Zhang, Xiao Guo, Liyan Zhou, Shangqian Zhao
Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
Ballistic transport and quantum confinements in low dimensional materials play important roles determining many interesting transport behaviors. In this talk we will discuss our progress in studying 1-dimension transport through single double-layered carbon nanotubes and gold nanowires. The interplay between the layered-structure of the former and ballistic transport of electrons in gold will be shown in details.
Spin Torque Effect in Spin-Filter Based Magnetic Tunnel Junction
Yu-Hui Tang(唐毓慧)1 , Fa-Chieh Chu(朱法杰)1 , and Nicholas Kioussis2
1 Department of Physics, National Central University, Jhong-Li, Taiwan
2 Department of Physics, California State University, Northridge, CA, USA
Recent discoveries in the ferromagnet/insulator/ferromagnet (FM/I/FM) magnetic tunnel junctions (MTJs) have demonstrated that the relative orientation of the two FM electrodes can be either altered by an external magnetic field, i.e. the tunneling magnetoresistance (TMR) effect, or controlled by a spin-polarized current, i.e. the current-induced magnetization reversal via the spin transfer torque (STT) effect. The spin-transfer, , and field-like, , components of the STT originate from different components of the spin current accumulated at the FM/I interface and can be expressed in terms of the interplay of spin current densities and of the non-equilibrium interlayer exchange couplings [1], respectively, solely in collinear configurations.
The insulator in conventional FM/I/FM MTJs plays only a passive role in the spin-polarized transport. The evolution beyond passive components has broadened the quest for multifunctional spintronic devices consisting of spin-filter (SF) barriers [2], which exploits the separation of the barrier heights of the two spin channels that can be in turn tuned via an external magnetic field.
In this study [5], the tight binding calculations and the non-equilibrium Green's function formalism is employed to study the effect of the SF-barrier magnetization on the bias behavior of both components of STT in noncollinear FM/I/SF/I/FM junctions. We predict a giant in contrast to conventional FM/I/FM junctions, which has linear bias dependence, is independent of the SF thickness, and has sign reversal via magnetic field switching. Our results suggest that the novel dual manipulation of either by a magnetic field or bias can be employed for “reading” or “writing” processes, respectively, in the next-generation field-like-spin-torque MRAM (FLST-MRAMs). Finally, our newly derived general expressions of noncollinear and allows the efficient calculation of the STT from collinear ab initio electronic structure calculations [3,4]. (Contract No. NSC 102-2112-M-008-004-MY3)
References:
- Y. –H. Tang et al., Phys. Rev. B 81, 054437 (2010).
- T. S. Santos and J. S. Moodera, Phys. Today 63, 46 (2010).
- X. Jia, K. Xia, Y. Ke, and H. Guo, Phys. Rev. B 84, 014401 (2011).
- Y. –H. Tang and F. –C. Chu, J. Appl. Phys. 117, 093901 (2015).
- Y. –H. Tang, F. –C. Chu, and N. Kioussis, Sci. Rep. 5, 11341 (2015).
Things Strange and Wonderful at the Nanoscale
Sokrates T. Pantelides
Department of Physics and Astronomy
and Department of Electrical Engineering and Computer Science
Vanderbilt University, Nashville, TN 37235 USA
and Materials Science and Technology Division
Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
The combination of density functional theory calculations and aberration-corrected scanning transmission electron microscopy is a powerful way to probe nanostructures with atomic resolution. In this talk I will describe a few recent examples: a) the discovery of a new form of crystalline order that we termed “interlaced crystals”, namely ABX2 tetrahedrally-bonded structures in which the two cations that share a sublattice can exist in a large number of ordered arrangements, giving rise to interlaced domains, while the underlying Bravais remains intact [1]; b) fabrication and characterization of ultrathin (three atoms across) nanowires out of a molybdenum dichalcogenide monolayers [2], and c) the demonstration of low-loss electron-energy-loss spectroscopy as a powerful complement to optical spectroscopies, but with spatial resolution [3].
References:
[1] X. Shen, E. A. Hernandez-Pagan, W. Zhou, Y. S. Puzyrev, J. C. Idrobo, J. E. Macdonald, S. J. Pennycook, and S. T. Pantelides, “Interlaced crystals having a perfect Bravais lattice and complex chemical order revealed by real space crystallography”, Nature Comm. 5, 5431 (2014).
[2] J. Lin, O. Cretu, W. Zhou, K. Suenaga, D. Prasai, K. I. Bolotin, N. T. Cuong, M. Otani, S. Okada, A. R. Lupini, J.-C. Idrobo, D. Caudel, A. Burger, N. J. Ghimire, J. Yan, D. G. Mandrus, S. J. Pennycook, and S. T. Pantelides, “Flexible metallic nanowires with self-adaptive contacts to semiconducting transition-metal dichalcogenide monolayers”, Nature Nanotech. 9, 436-442 (2014).
[3] M. D. Kapetanakis, W. Zhou, M. P. Oxley, J. Lee, M. P. Prange, S. J. Pennycook, and S. T. Pantelides, "Atomically resolved maps of valence electron excitations with application to graphene", submitted for publication.
Supramolecular Materials for Future Devices: Investigating Structure, Electron and Spin States
N. Ballav1, M. Stöhr2,7, J. Lobo-Checa2,8, P. M. Oppeneer3, L. H. Gade,4 S. Decurtins, F. Diederich, C. Thilgen, A. Kleibert1, T. A. Jung1
1 Department of Synchrotron Radiation, Paul Scherrer Institute, Switzerland
2 Department of Physics, University of Basel, Switzerland
3Dept. of Physics and Astronomy, Uppsala University, Sweden
4University of Heidelberg, Germany
5Departments of Chemistry ETH Zürich, Switzerland,
6University of Bern, Switzerland
7Zernike Institute for Advanced Materials, University of Groningen, Netherlands
8Centro de Física de Materiales (CSIC-UPV/EHU),San Sebastián, Spain
E-mail:
Well defined electronic and spintronic interfaces can be architectured by combining self-assembly and surface science. The atomically clean metal surface in the ultra-high vacuum provides a very specific environment affecting the behaviour of the ad-molecules as well as the adsorbent-adsorbate interaction. Depending on the bonding at the interface, complex electronic and magnetic interactions can occur which can be explored by spectro-microscopy correlation, in this case photoemission and X-ray photoabsorption spectroscopy (PES, XAS) and scanning tunnelling microscopy (STM).
The emergence of quantum dot states from the interaction of a porous network with the 2D (Shockley) surface state of Cu(111) exhibits sufficient residual coupling to show the onset of a band-like structure in angle resolved photoemission [1]. Selected surface-supported molecules have been shown to exhibit ferromagnetic [2] or anti-ferromagnetic [3] exchange interaction, and their spin systems have been shown to be tunable by physical parameters and / or chemical stimuli [4]. Supramolecular chemistry can be combined with on-surface coordination chemistry to reversibly switch the spin of self-assembled bi-molecular arrays [5].
All these examples have in common that the substrate-molecular interfaces are well defined by their production from atomically clean substrates and molecular building blocks. The physics and chemistry of these unprecedented systems, which are addressable by scanning probes, provide insight into novel materials in their assembly, their electronic and spintronic properties which emerge from the interaction of their components down to the scale of single atoms, molecules and bonds.
References:
[1] J. Lobo-Checa et al. Science 325, 300 (2009)
[2] A. Scheybal et al. Chem. Phys. Lett. 411, 214 (2005)
[3] D. Chylarecka et al. J. Phys. Chem. Lett. 1, 1408–1413 (2010)
[4] C. Wäckerlin et al. Nature Communications 2010, 1:61 DOI: 10.1038/ncomms1057
[5] C. Wäckerlin et al. Advanced Materials 25, 2404-2408 (2013)
[6] For a complete list of contributing authors refer to the individual publications
Synthesis and Assembly of Nanoparticle Catalysts for Efficient Electrochemical Reduction Reactions
Shouheng Sun
Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
Recent advance in nano-fabrication has made it possible to design and synthesize nanoparticles with nearly precise controls of nanoparticle size, shape, composition and structure for catalytic applications. In this talk, I will summarize the common methods we used to synthesize monodisperse nanoparticles, especially intermetallic nanoparticles, core/shell nanoparticles, nanowires and their self-assemblies on graphene (or N-doped graphene) surface. I will use Au-, Pt-, and Cu-based elemental and alloy nanoparticles as examples to demonstrate the rational tuning and enhancement of nanoparticle catalysis for selective electrochemical reduction of proton, oxygen, and carbon dioxide for renewable energy applications.
Growth of Small Organic Molecules on A Variety of
Graphene Substrates
Christian Teichert
Institute of Physics, Montanuniversität Leoben, Franz Josef Str. 18, 8700 Leoben, Austria
* ;
Crystalline films of small semiconducting organic molecules offer attractive potential for optoelectronic applications on flexible substrates. However, these applications require a transparent and flexible electrode material; and here the novel material graphene (Gr) comes into play. Since small conjugated molecules like the rod-like molecule para-hexaphenyl (6P) fit well to the hexagonal structure of graphene, growth of 6P on Gr can be expected in a lying configuration.
As observed in situ by low-energy electron microscopy, 6P grows at 240 K indeed in a layer-by-layer mode with lying molecular orientation on Ir(111) supported graphene [1]. 6P islands nucleate at Gr wrinkles [2]. At higher temperatures, needle-like 6P crystallites - also composed of lying molecules - are found [3]. On exfoliated, wrinkle-free graphene, such needles develop with discrete orientations defined by the Gr lattice as detected by atomic-force microscopy [4]. Interestingly, for few-layer exfoliated Gr the needle length decreases significantly with increasing layer number [5].