Scanning Tunnelling Microscopy and Atom Manipulation

.....Visualizing, probing and manipulating matter at the atomic scale

 

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Aparna Deshpande,

Assistant Professor, Physics

IISER Pune Dr. Homi Bhabha Road,

Pashan, Pune 411008, INDIA

 

email: aparna.d@iiserpune.ac.in


About me

I did B.Sc in Physics from D. G. Ruparel College, Mumbai followed by M.Sc in Physics from Mumbai University. I completed my PhD in Physics at Ohio University, Athens, Ohio, USA in 2007. I did my postdoctoral research work at University of Arizona, Tucson, Arizona, USA and at Northwestern University, Evanston, Illinois, USA. I joined as a faculty member at IISER Pune in August 2011.

Research Interests

Low dimensional systems at nanometer length scale have unique properties. The electrons in these systems are confined to one or more dimensions. This gives rise to a variation in the density of states of these systems. Also various interactions like electron-electron interaction, electron-phonon interaction, electron-plasmon interaction emerge in different systems. My research is focussed on the investigation of low dimensional systems like surfaces and thin films (two-dimensional), nanotubes and chains (one dimensional), and nanoparticles and quantum dots (zero dimensional) using scanning tunnelling microscopy (STM). The high spatial resolution of STM provides real space images with atomic resolution. With scanning tunnelling spectroscopy performed using STM at low temperature (4.2 K), the enhanced energy resolution at low temperature allows a direct measurement of the local electronic properties of these systems. The atomic scale structure and electronic information provides an insight into the quantum phenomena and interactions in these systems.

Surface functionalization of conducting surfaces using molecular self-assembly is one of the routes towards developing newer and better materials for applications. My interest lies in exploring different molecules and testing their self-assembly on surfaces. The process of functionalization can be investigated using STM imaging and spectroscopy to shed light on molecule-surface interactions, ordering of molecules on the surface and charge transfer processes.

Another area of my interest is to use the STM as an active tool for atom and molecule manipulation. Using STM manipulation techniques the position and charge state of an atom on the surface can be altered as desired. Also the chemical structure of a molecule can tuned at the atomic level for nanoelectronic and spintronic device applications.

Current Research Topics

1.    Dirac materials, graphene and beyond

2.    Layered materials

3.    Low dimensional electron systems

4.    Surface functionalization with molecular self-assembly

Research Lab

My lab (Scanning Tunnelling Microscopy and Atom Manipulation), room 214, is in the h-cross block of IISER main campus. The h-cross block is specially designed to house all experimental physics labs. Utmost attention has been paid to details like uninterrupted power supply, vibration isolation areas, and custom built interiors for every lab.

The main instruments in my lab are-

1.    Omicron STM operating in ultra high vacuum (UHV) and at low temperature (LT), 77 K and 4.2K (UHV-LT-STM) for dedicated STM, spectroscopy and atom and molecule manipulation experiments at 77 K and 4.2 K

 

 

 

 

2.    Nanosurf atomic force microscope (AFM) and STM, table top models, for projects at room temperature (300 K) and in ambient environment

PhD students

Sk Rejaul joined in August 2012

Imrankhan Mulani joined in August 2015

 

Selected Publications

1.    Rejaul Sk, Srilatha Arra, Barun Dhara, Joel S. Miller, Mukul Kabir, and Aparna Deshpande, "Enhancing the Intermolecular Interaction by Cyano Substitution in CuPc", 10.1021/acs.jpcc.7b09225

2.    Sumati Patil, Sadhu Kolekar, Aparna Deshpande, "Revisiting HOPG superlattices: Structure and conductance properties", Surface Science, 658, 55-60, (2017)

3.    Rejaul Sk, Mandar Shirolkar, Barun Dhara, Sulabha Kulkarni, and Aparna Deshpande,"Enhancing the thermopower and tuning the resistivity in Bi2Se3 with Fe-doping", Chemical Physics Letters, 638, 94 (2015)

4.    Aparna Deshpande, Chun-Hong Sham, Justice M. P. Alaboson, Jonathan M. Mullin, George C. Schatz, and Mark C. Hersam, Self-Assembly and Photopolymerization of Sub2 nm One-Dimensional Organic Nanostructures on Graphene, J. Am. Chem. Soc., 134, 16759 (2012).

5.    Aparna Deshpande, Wenzhong Bao, Zeng Zhao, Chun Ning Lau, and Brian LeRoy, Imaging charge density fluctuations in graphene using Coulomb blockade spectroscopy, Phys. Rev. B, 83, 155409 (2011). Accompanying synopsis in Physics, http://physics.aps.org/synopsis-for/10.1103/PhysRevB.83.155409

6.    Aparna Deshpande and Brian LeRoy, Smoothing the ripples, Invited Highlight, ChemPhysChem, http://onlinelibrary.wiley.com/doi/10.1002/cphc.201000026/pdf (18 February 2010).

7.    Aparna Deshpande, Wenzhong Bao, Zeng Zhao, Chun Ning Lau, and Brian LeRoy, Mapping the Dirac point in gated bilayer graphene, Appl. Phys. Lett., 95, 243502 (2009).

8.    Aparna Deshpande, Wenzhong Bao, Feng Miao, Chun Ning Lau, and Brian LeRoy, Spatially resolved spectroscopy of monolayer graphene on SiO2, Phys. Rev. B, 79, 205411 (2009). Accompanying synopsis in Physics, http://physics.aps.org/synopsis-for/10.1103/PhysRevB.79.205411

9.    Aparna Deshpande, Dandapani Acharya, Joel Vaughn, Saw-Wai Hla, Handan Yildirim, Abdelkader Kara, and Talat Rahman, Atom-by-atom extraction using scanning tunneling microscope tip-cluster interaction, Phys. Rev. Lett., 98, 028304 (2007).

10. Violeta Iancu, Aparna Deshpande and Saw-Wai Hla, Manipulating Kondo Resonance in Two-Dimensional Molecular Self-Assembly, Phys. Rev. Lett., 97, 266603 (2006).

Teaching

1.    PHY330: August to December 2017: Physics Lab for third year BS-MS and iPhD students

2.    PHY350: January to May 2017: Electronics II: Electronics lecture course for BS-MS and iPhD students

3.    PHY222 : January to May 2016: Physics Lab for second year (4th semester) BS-MS students

4.    PHY221: August to December 2015: Physics Lab for second year (3rd semester) BS-MS students

5.    PHY350: January to May 2015: Electronics II: Electronics lecture course for BS-MS and iPhD students

6.    PHY221: August to December 2014: Physics Lab for second year (3rd semester) BS-MS students

7.    PHY121 : August to December 2013: Introductory Physics Lab for first year (1st semester) BS-MS students

8.    PHY430 : January to May 2013: Advanced Physics Lab for fourth year (8th semester) BS-MS and iPhD students

9.    PHY415 : August to December 2012: Advanced Physics Lab for fourth year (7th semester) BS-MS and iPhD students

10. PHY222 : January to May 2012: Physics Lab for second year (4th semester) BS-MS students

11. PHY121 : August to December 2011: Introductory Physics Lab for first year (1st semester) BS-MS students

Complete CV

My detailed CV can be found here.

Links of interest

http://physics.aps.org/

http://www.itcsra.org/

http://www.saxontheweb.net/

http://www.trekkinginhimalayas.com/

IISER main page

 

If you are interested in working in my lab as a BS-MS, iPhD or PhD student please feel free to contact me at aparna.d@iiserpune.ac.in

 

......The test of all knowledge is experiment - Richard Feynman......