contact details
					Department of Theoretical Physics Research School of Phys. Sc. and Eng. Institute of Advanced Studies The Australian National University Canberra, ACT 0200, Australia Room: 103 Le Couteur Building Telephone +61 2 6125 3066  Fax: + 61-2- 6125 4676 E-mail mukunda.das@anu.edu.au

Research Interests

My research work is in the general area of theoretical condensed matter physics.
Condensed matter physics has a goal of understanding the structure and properties of all kinds of solids and liquids. It is a very broad and lively area of research, where one witnesses frequent occurrence of novel phenomena relating to exotic properties of matter in semiconductors, superconductors, magnets etc. Due to intense research all over the world in this area, new ideas and novel materials are created. Needless to say, today Condensed matter physics is one of the main pillars of high technology.

In this highly active area my research interest is concerning the fundamental aspects of condensed matter, which include

Some highlights of our recent work:

• High Tc superconductivity and vortex matter phase transition.

In the bulk high Tc superconductors (HTcS) the critical current in presence of a magnetic field is lower by an order of magnitude compared with that of low Tc superconductors. The low critical current is due to weak pinning of the vortices in the mixed phase. At high magnetic field and at high temparature, the vortex lattice seems to melt to a vortex liquid state causing dissipation. We have developed a first principle density functional theory of vortex matter. In this theory the freezing temperature of the vortex liquid is calculated for various applied magnetic fields, thus generating the freezing phase boundary. Our results are analysed in relation to experimental data. We also found that there exists a " vortex gas phase" above the first critical field below Tc.. Thus we predict a reentract phase which is now verified in resistivity and magnetisation experiments.

• Strongly Correlated Systems

Strong electronic correlations seem to influence the physical properties of solids resulting in peculiar anomalies. By using the slave boson formalism in a Hubbard model we have studied metal-insulator transition and have analysed as a function of doping the competition between a charge density wave phase induced by oxygen breathing modes, antiferromagnetic order and paramagnetism. Our analyses explain a number of qualitative features observed in the normal states of the underdoped phase of the oxide superconductors. In this work we have emphasised the role of phonons in the strong correlation models. We have also studied zinc doping in place of copper in CuO2 planes. Our theory revels formation of local moments near the impurity sites.

• Electronic Transport and Noise in Mesoscopic Degenerate Systems

In earlier days noise was considered as unwanted. Currently it is viewed as a phenomenon that carries important information about a physical system. During the past five years we have been studying mesoscopic transport and noise. Our methods are technically rigorous and manifestly consistent with all relevant physical constraints. Surprisingly, other well established theories are in conflict with ours, despite their widespread adoption over recent years. The clear implication is that these established accounts of noise are at odds with basic principles.

In a series of recent published critiques we have identified how these violations occur. We have shown that the models in question are liable to need deep revision, to regain any credibility as eventual platforms for practical device engineering. The wider significance of our work puts it in a field in which the interplay of open boundary conditions (imposed from outside) and of the microscopic dynamics (within the system) demands careful treatment. The key ingredients of our work involves interparticle correlations via the Landau's Fermi liquid theory, an aspect generally ignored in the popular literature.

Selected recent publications :

• CONDENSED MATTER THEORIES,VOL.17, (with F. Green) Edited, Nova Sc, New York (2003) pp. 387.

• Mesoscopic transport as manybody physics (with F. Green) in Condensed Matter Theories,Vol.17, Ed. M. P. Das and F. Green, Nova Sc, New York (2003) 83-102.

• Excitonic Superconductivity in Charge Injected Organics (with F. Green) Nonlinear Optics (2002) to appear

• Transport and noise in mesoscopic conductors: A conservative view (with F. Green) in Noise and Fluctuations Control in Electronic Devices, Ed. A. Balandin, Am Scientific Publ., USA (2002).

• Dynamical theory of strongly coupled two-dimensional Coulomb fluids in the weakly degenerate quantum domain (with K. I. Golden and F. Green), Phys Rev E 64 (2001) 046125 1-13.

• Classical to quantum crossover in high-current noise of one-dimensional ballistic wires (with F. Green), Fluctuation and Noise Lett. 1 (2001) C21-C33.

• Aspects of transport and noise for mesoscopic charge detectors (with F. Green) in
  Experimental Implementation of Quantum Computation (IQC'01) Ed. R. Clark, Rinton Press , Princeton,USA (2001) 335-339.

• Shot noise in mesoscopic quantum systems (with F. Green) in Condensed Matter Theories,Vol.16, Ed. S. Hernandez and J. Clark, Nova Sc, New York (2001) 29-39.

• Shot noise in fractional quantum Hall systems (with F. Green) in Science and Technology of Nanostructured Materials, Editors. B. K. Rao, S. M. Bose, M. P. Das, and S. N. Sahu, Nova Scientific , New York (2001) 217-222.

• SCIENCE AND TECHNOLOGY OF NANOSTRUCTURE MATERIALS, (with B. K. Rao, S. M. Bose, and S. N. Sahu), Edited. Nova Scientific, New York (2001).

• Compressibility sum rule for the two dimensional electron gas (with K. I. Golden and F. Green, Phys. Rev. E 64 (2001) 012103,1-

• On the 'anomalous' resurgence of shot noise in long conductors (with F. Green) Australian J. Physics 53 (2000)499-512.

• Comments on ' Conductance and shot noise for particles with exclusion statistics' by Isakov, Martin and Ouvry (with F. Green), Phys. Rev. Lett. 85 (2000) 222.

• Coulomb screening in mesoscopic noise: a kinetic approach (with F. Green) J. Phys. Cond.Mat. 12 (2000) 5251-5273. (cond-mat/9911251)

• High field noise in metallic diffusive conductors (with F. Green) J. Phys. Cond.Mat. 12 (2000) 5233-5250.(cond-mat/9809339).

• Kinetic approach to mesoscopic noise (with F. Green) in Condensed Matter Theories Vol 15, Editors G. S. Anagnostatos, R. F. Bishop, K. A. Gernoth, J. Ginis and A. Theophilou , Nova Science, New York (2000) 403-414.

• Bose-Einstein condensation of atoms with attractive interaction in a harmonic trap ( with N. Akhmediev and A. Vagov) Australian J. Phys. 53 (2000) 157-165.

• Mesoscopic Noise Theory: Microscopics or Phenomenology? (with F. Green) in Unsolved Problems of Noise and Fluctuations, Editors D. Abbott and L. B. Kish, American Institute of Physics, 511 (2000) 422-433.

• CONDENSED MATTER IN ZERO, ONE AND TWO DIMENSIONS (with D.Neilson) Edited,Proceedings of 9th Gordon Godfrey Workshop on Condensed Matter Physics : CSIRO Publishing, Melbourne (2000).

• BOSE-EINSTEIN CONDENSATION: atomic physics to quantum liquids (with C. Savage) Edited, Proceedings of 13th Physics Summer School : World Scientific Publ., Singapore (2000) .This is also published as a Supplementary Issue of 'The Modern Physics Letters B' Sept, 2000.

• NANOSTRUCTURES AND QUANTUM CONFINEMENTS
  Proceedings of Workshop (Edited) held in the Australian National University, Nov- Dec (1998)
  Special Issue of Australian J. Physics , 53, No.1 (2000).

• Normal state anomalies in high Tc superconductors
  Proc. Third Rencontres du Vietnam, Superconductivity, Magneto-Resistive Materials and Strongly Correlated Quantum Systems, Editors Nguyen Van Hieu, Tran Thanh Van and Gang Xiao (Vietnam National Univ Press, Hanoi) (1999) 51-53.

• Mesoscopic Noise Theory: Microscopics, or Phenomenology? ( with F. Green) Proc. 2nd International Conference on Unsolved Problems of Noise, Editors: D. Abbott and L. B. Kiss, Adelaide, (AIP).(cond-mat/ 9905086)

• PHYSICS OF NOVEL MATERIALS, Proceedings of Tenth Physics Summer School (Edited) World Scientific Publ.,Singapore (1999).

• Bose-Einstein condensation of atoms with attractive interaction (with N. Akhmediev and A. Vagov) International J. Modern Physics, B 13 (1999) 625-631.

• Density Functional Theory of Super-Phenomena in Condensed Matter Theorie Vol 14, Editor D. Ernst, Nova Science, New York (1999) 97-103.

• FUTURE DIRECTIONS FOR CONDENSED MATTER PHYSICS (with D. Neilson) Proceedings of 8th Gordon Godfrey Workshop on Condensed Matter Physics (Edited) :CSIRO Publishing, Melbourne (1999).

• Novel superconducting mechanism in coupled electron-hole layers (with J. S. Thakur and D. Neilson) Physical Review B 57 (1998) 1801-1804.

• Some ground state properties of 3d and 4d metals studied using the generalised gradient approximation ( with K. Kokko) J. Phys. Condens Matter 10 (1998) 1285-1291.

• Effect of Cu site Co,Ni and Ga substitution on the superconductivity of tetragonal LaBaCaCu3O7 system (with V. P. S. Awana, J. Horvat, H.K.Liu, S.X.Dou, R. Singh and A.V. Narlikar) Physica-C 301 (1998) 205-214.

• Local moment formation in zinc-doped cuprates ( with B. C. den Hertog) Phys. Rev.B 58 (1998) 2838-2843.

• ELECTRONIC DENSITY FUNCTIONAL THEORY: Recent Progress and New Directions (Edited with J. F. Dobson and G. Vignale) Plenum Press, New York (1998).

• Brief Introduction to Density Functional Theory in Electronic Density Functional Theory. Editors J. F. Dobson, G. Vignale and M. P. Das, Plenum Press, New York (1998) 3-18.

• Density Functional Theory of Super-Phenomena in Condensed Systems in Electronic Density Functional Theory. Editors J. F. Dobson, G. Vignale and M. P. Das, Plenum Press, New York (1998) 373-378.

• Ground State Properties of 3d and 4d Metals: A Study via GGA Made Simple ( with K. Kokko) in Novel Materials Design and Properties, Editors B. K. Rao and S. N. Behera. Nova Science Publ. (1998) 405-410.

• Bose-Einstein condensation of trapped alkali atoms with attractive interaction ( with N.Akhmediev and A. Vagov) Proc. IX International Conference on Recent Progress in Many- Body Theories, Editors: D. Neilson and R.F.Bishop, World Scientific, Singapore,(1998) 287-292.

• High field fluctuations in mesoscopic metals (with F. Green) Proc. IX International Conference on Recent Progress in Many-Body Theories, Editors: D. Neilson and R.F.Bishop, World Scientific, Singapore, (1998) 102-105.

• Stability of the pancake vortex lattice in a two-layered superconductor (with D. J. C. Jackson) Condensed Matter Theories Vol 13, Editors J. da Providencia and F. B. Malik, Nova Science, New York (1998) 287-294.

• Electron ejection from clean metallic surfaces upon charged particle impact ( with J. Berakdar) Physical Review A 56 (1997)1403-1413

• Zinc valency and local moments in impurity doped cuprates (with B. C. den Hertog) Physica C 282- 287 (1997) 1709-1710.

• Bose-Einstein ondensation of Atoms with Attrcative Interaction (with N. Akhmediev and A. Vagov) in Condensed Matter Theories Vol 12, Editors J. W. Clark and P. V. Panat, Nova Science, New York (1997) 17-26.

• Slave Boson treatment of metal-insulator transition in CuO planes at zero and finite doping (with B. C. den Hertog) Solid State Comm, 98 (1996) 7-10.

• A possible new type of superconductivity (with L. J. Tassie) Modern Phys.Lett.10B (1996) 173-179.

• Normal state phase of CuO planes in high Tc superconductors ( with B. C. den Hertog) Physical Review B54 (1996) 6693-6699.

• Melting of the flux line lattice: a review (INVITED) ( with D. J. C. Jackson) Superconductor: Science and Technology (1996) 9, 713-727.

• ATOMIC AND ELECTRON FLUIDS Proceedings of 4th Gordon Godfrey Workshop on Condensed Matter Physics (Edited with D. Neilson) CSIRO Publishing, Melbourne (1996).

• Phase Transition in Vortex Matter (with D. J. C. Jackson) in Condensed Matter Theories Vol 11, Editors E. Ludena, P. Vashishta and R. F. Bishop,, Nova Science, New York (1996) 473- 482.

• Freezing of vortex liquid in high temperature superconductors, J. Korean Phys. Soc. (1996) 29S, 149-51.