Objective. Present Position: Senior Assistant Professor at Department of Applied Physics Aligarh Muslim University., Aligarh U.P.

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1 Pushpendra Tripathi M.Sc., M.Phil., Ph.D. (Physics) Department of Applied Physics, ZHCET, Aligarh Muslim University Aligarh, UP Tel: (Mobile) (Res.) ptrip71@yahoo.com pushpendratripathi@rediffmail.com Personal Information Date of Birth: 5 th September 1971 Place of Birth: Chhatarpur, India Father s name: K.S. Tripathi Nationality: Indian Marital Status: Married Present address: Centre of Excellence in Nanomaterials, Department of Applied Physics,, Faculty of Engineering & Technology (ZHCET), Aligarh Muslim Aligarh U.P., India Permanent address: Near Rani Durgawati School, Chaubey Colony, Chhatarpur , M.P. India. Gender: Male Objective As a continuation to my background in Physics condensed matter Physics (Low Dimensional systems and Nanomaterials) and subsequent more than 17 years of experience in academic and research, I wish to continue academic and research/teaching career. My research interest s lies in general field of Condensed matter Physics with particularly low dimensional systems and synthesis and charterisiation of nanoparticles Present Position: Senior Assistant Professor at Department of Applied Physics Aligarh Muslim University., Aligarh U.P. Professional Experience I have more than 17 years of research experience after Ph.D. degree. Also, I have 9 academic years of teaching experience as a Lecturer at UG and PG level. The details of the experience are as follows:

2 DETAILS OF EMPLOYMENT (Starting from the present position) A. Teaching Employment Sl. No. Employer Designation Last pay drawn with pay scale Nature of assignment Period From To 1. A.M.U., Aligarh Assistant Professor 29,900+DA+HRA+others allowances Teaching 6/9/2010 continue 1. M.S. Temporary teaching assistant Rs. 17,000/- Teaching 24/6/2010 5/9/ M.S. 2. M.S. 3. M.S. 4. M.S. 5. M.S. 6. M.S. Temporary Lecturer Temporary Lecturer Temporary Lecturer Temporary Lecturer Temporary Lecturer Temporary Lecturer Rs DA+HRA Rs DA+HRA Rs DA+HRA Rs DA+HRA Rs DA+HRA Rs DA+HRA Teaching 26/6/ /5/2010 Teaching 24/6/ /5/2009 Teaching 14/7/ /5/2005 Teaching 16/7/ /5/2004 Teaching Sept Dec.2000 Teaching 16/9/ /5/1999 B. experience and employment Sl. No. Employer Designation Last pay drawn with pay 1. D.S.T., New Delhi 2. University of Essex, U.K. Scientist under fast track young scientist project Senior Officer scale Rs. 20,000/- pm 23,100 pa Nature of assignment work work for Post-doc research Period From To 1/6/ /5/2008 1/1/ /11/2002

3 3. M.S. 4. M.S. 5. Jiwaji Gwalior Senior fellow Junior Fellow Assistant Rs HR A Rs HR A Rs. 1200/-pm work for Ph.D. Degree work for Ph.D. Degree work for M.Phil. course Sept Sept Sept August, 1998 August, 1997 August 1994 COURSES TAUGHT At Post Graduate level: Quantum Mechanics Nanocomposites Properties of nanomaterials At Graduate level: Electricity & Magnetism, Electronics, Optics, mechanics Modern Physics and Engineering materials and material science Laboratory Experience: COMPUTATIONAL SKILLS: - More than 18 years working experience on WINDOWS, DOS, LINUX and UNIX environment. - Knowledge of high-level computer languages and software s. i.e. FORTRAN 95, Mathematica, Matlab etc. - Developed applications program for research work in the area of theoretical condensed matter Physics. Instruments Lab Expereince - Guided B.Tech, M.Tech (Nanotechnology), F.Y., S.Y. and T.Y. Lab experiments. Details of sponsored/consultancy Projects handled Title : Transport Properties of Nitride structure No. SR/FTP/PS/ Funding agency: Department of Science and Technology, New Delhi, India. Amount: Rs. 10,64000/- Duration of the project: Three years i.e 1/1/ /5/2008

4 RESEARCH SUPERVISION: Ph.D. student awarded: 1 Ph.D. students presently: 3 M.Phil. Student: 1 Completed M. Tech/Ad. P.G. diploma project : 12 Ph.D Thesis 1. Natural Radioactivity and Ionizing Radiation Measurement in Environment, by Mohd. Zubair, Assessment of Radium, Radon and Their Progeny in Human Environment using Solid State Nuclear Track Detectors, by Deepak Verma, M. Tech/Ad. PG Diploma Thesis: 1. A synthesis and characterization of ZnO and Ni doped nanoparticles by Sol-Gel Method. Mohd. Naseem Siddique (12-APNM-515) Prepartion and Characterization of Graphene-Silver Sulfide Hybrid (G-Ag 2S). Mohd. Maseehuzzama (2014). 3. The Characterization of natural mesoporous calcium carbonate nanomaterials and assessment of its physical, chemical and biological properties. Mohd. Furquan (11-APM-509) Synthesis and Characterization of ZnO and Mg doped ZnO nanoparticles by Sol-gel process. Mohd. Meenhaz Ansari (11-APM-507) Synthesis and Characterization of biosurfactant surface modified Fe 3O 4 nanoparticles and assessment of its antibacterial activity. Faria Khatoon Naqvi (12PGD-539) Role of ZnO Morphology on the Fracture toughness of spark plasma sintered hydroxyapatitie-zno composite. Ambreen Nisar (2010-APM-503) Synthesis and Characterisation of pure and zinc doped cobalt ferrite nanoparticles by sol-gel autocombustion. Priti Yaduvanshi (10-APM-510) Effect of organic groups (methyl, Phenyl, Dimethyl) on Properties of organic-inorganic hybrid Sol-gel coatings on Surface Modified stainless steel 316. Nirmal Kumar (09-APM-515) Nanotechnology business and products. Nazim Khan (09-APM-507), 2011.

5 Details of visits abroad: Sl. No. Country Organization Purpose Period 1. United Kingdom University of Essex, UK 2. Scotland UK University of Edinburgh. UK 3. Israel Tel-Aviv Israel 4. Sweden Linköping Sweden Post-doc Participated in conference visit Conference visit Details of Orientation/ short term course From To Nov Jan Sr. Name of the course Period University/Institute No. From To 1. Refresher Course in 22/07/ /08/2015 UGC Academic Staff Environmental Studies College, Aligarh Muslim Aligarh, India 1. Refresher Course in 27/02/ /03/2015 UGC Academic Staff Computer Application College, Aligarh Muslim Aligarh, India 2. Short term course on Health/Wellbeing Awareness Orientation programme 4. Short term course on Nanoscience and nanomedicine : from bench to bedside 5. Course on Computational Physics 02/09/ /09/2013 UGC Academic staff college, Aligarh Muslim Aligarh, India 13/07/ /08/2012 UGC Academic staff college, Aligarh Muslim Aligarh, India 04/06/ /06/2012 Indian Institute of Technology, Roorkee, India 10/02/ /02/1996 Bhabha Atomic center, Mumbai, India

6 Education i) University of Essex, England (U.K.) Jan Nov Post-Doctorate in Theoretical condensed matter Physics (Semiconductor Physics Theoretical modelling). from to ii) M.S. Barodo, India May, 2000 Ph.D. in May, 2000 from Physics Department, Faculty of Science, M.S., India in the field of Theoretical Condensed Matter Physics. The title of thesis is Electron-electron scattering and Electron-impurity scattering and its effects on the properties of Semiconductor Superlattices iii) Jiwaji Gwalior, India June, 1993 M.Phil. in 1993 with 63.25% marks from School of Studies in Physics, Jiwaji Gwalior, India, in the field of Theoretical Solid Sate Physics. The title of my M.Phil. dissertation is Plasmons in Semiconductor Superlattices. iv) A.P.S. Rewa, India June, 1992 M. Sc. Physics (Electronics ) in 1992 with 70% marks from A.P.S. Rewa (M.P.), India. v) A.P.S. Rewa, India June, 1990 B.Sc. Physics, Maths and chemistry with 55% marks from A.P.S. Rewa, India. vi) M.P. Board Bhopal, India April, 1986 Higher Secondary, science subjects with 55% marks from M.P. Board, Bhopal, India. Scholarships and fellowships or Medals details. 1) Received merit school fellowship in local body examination class, During, ) Awarded assistant fellowship of Dr. AC Sharma research UGC project during M.Phil. tenure at Jiwaji Gwalior from Sept Oct ) Awarded JRF at MS, during Ph.D. tenure from Sept Augest ) Awarded SRF at MS, during Ph.D. tenure from Sept Augest ) Awarded Post-Doctorate research fellowship from University of Essex, Colchester, UK for 2 years i.e. Jan Dec

7 6) Awarded Young Scientist Fast Track project from DST, New Delhi for 3 years i.e. June 2005-May The total cost of project was 10,64,000/- 7) Awarded 2 months research fellowship from Tel-Aviv Tel-Aviv, Israel, from 15, Nov to 15, Jan Published papers in journals and conference proceedings: 30 National conference attended: 28 International conference attended: 4 LIST OF PUBLICATIONS: [1] Electric transport and enhanced dielectric permittivity in pure and Al doped NiO nanostructures, M. Naseem Siddique, Ateeq Ahmed, P. Tripathi, Journal of Alloys and Compounds 735 (2018) [2] Enhanced room temperature ferromagnetism in Ni doped SnO2 nanoparticles: A comprehensive study, Ateeq Ahmed, T. Ali, M. Naseem Siddique, Abid Ahmad, and P. Tripathi, JOURNAL OF APPLIED PHYSICS 122, (2017). [3] Photocatalytic performance of Fe-doped TiO2 nanoparticles under visible-light irradiation, Materials Express (2017) [4] Band gap engineering and enhanced photoluminescence of Mg doped ZnO nanoparticles synthesized by wet chemical route, Mohd, Arshad, Mohd Meenhaz Ansari, Arham S. Ahmed, Pushpendra Tripathi, S.S.Z. Ashraf, A.H. Naqvi and Ameer Azam, Journal of Luminescence, , 2015 ( impact factor 2.236). [5] Disorder Assisted Acoustic Energy Relaxation in Quantum Wells, S.T. Hasan, P. Tripathi, S.S.Z. Ashraf & A.C. Sharma, Phys. Scr.89 (2014) (impact factor 1.293) [6] Dynamic Deformation Electron-Phonon Interaction in Disordered Bulk Semiconductors, P. Tripathi, S.S.Z. Ashraf, S.T. Hasan and A.C. Sharma, World Journal of Condensed Matter Physics 2012, 2, [7] Energy relaxation in two dimensional electron gas with dynamic deformation potential, S.S.Z. Ashraf, P. Tripathi, S.T. Hasan and A.C. Sharma, Physica E- Low- Dimensional Systems & Nanostructure, 42, 87 (2009). (Impact Factor:,1.532 Citation: 02) [8] Electron Phonon Relaxation in Disordered Semiconductor Quantum Well with Dynamically Screened Deformation Potential S. S. Z. Ashraf, P. Tripathi, A.C. Sharma & S.T. Hasan, J. Phys.:Cond.Matter 21, (2009). (Impact Factor: Citation: 02)

8 [9] Energy exchange rate in non-degenerate electron gas confined to a GaAs heterostructure. P. Tripathi and A.C. Sharma, Modern Physics Letters B, 21, , (2007). (Impact Factor: 1.10) [10] Dynamically-screened electron-electron scattering in 2D, P. Tripathi and B.K. Ridley, J. Phys.: Condensed Matter, 15 (7) 1057, (Impact Factor: Citation:03) [11] Dynamics of Hot-Electron Scattering in GaN Heterostructures, P. Tripathi and B.K. Ridley, Phys. Rev. B (2002). (Impact Factor: 3.45, Citation: 15) [12] Electron-electron energy exchange rates in a 2D non-degenerate gas, P. Tripathi and B.K. Ridley, 26th International conference on the Physics of Semiconductors ICPS, Edinburgh, edited by A.R. Long and J.H. Davies, Institute of Physics publishing (2002). [13] Relaxation Time for a Charge Carrier due to its scattering from other Charge Carriers in superlattices, A.C. Sharma and P. Tripathi, Physica E- Low-Dimensional Systems & Nanostructure, 8, (2000). (Impact Factor: 1.546) [14] Magneto-plasma and their Lineshapes for a Compositional and Doping Superlattices of Type-II, A.C. Sharma, P. Tripathi, R. Sen and N. Jain, Indian Journal of Pure & Applied Physics, 37, 545 (1999). [15] Plasmons and their Damping in a Doped Semiconductor Superlattice, P. Tripathi and A.C. Sharma, Pramana J. Phys. 52, 101 (1998). (Impact Factor: 0.50) [16] Collective Excitation and their Lineshapes for a Compositional Superlattice of Type-II, A.C. Sharma, R. Sen and P. Tripathi J. Phys.: Condensed Matter 9, (1997). (Impact Factor: 2.546) [17]Structural Phase Analysis, Band gap Tuning and Thermal Properties of TiO2/ZnO Nanoomposite, AIP Conf. Proceedings (2017). [18] Influence of Fe ion on structural, optical and dielectric properties of SnO2, Ateeq Ahmed *, *P. Tripathi, Wasi Khan and Alim H. Naqvi, AIP Conf. Proc. 1731, (2016). [19] Polyethylene Glycol (PEG) Assisted Size-Controlled SnO2 Nanoparticles By Sol- Gel Process, AIP Conf. Proc. 1731, (2016). [20] Study of ZnO and Mg doped ZnO nanoparticles by Sol-Gel process, Mohd Meenhaz Ansari*, Mohd Arshad and P. Tripathi, AIP Conf. Proc. 1665, (2015);

9 [21] The Study and Characteristics of ZnO/CdS Nanocomposite and Its Application on Nanoantibacterial Activities, Tinku Ali, P.Tripathi, NashiruddinAhammed 1 and S.S.Z Ashraf, AIP Conf. Proc. 1665, (2015); [22] Study of ZnO and Mg doped ZnO nanoparticles by Sol-Gel process, Mohd Meenhaz Ansari*, Mohd Arshad and P. Tripathi, AIP conference Proc in press, [23] Energy Loss Rate in Disordered Quantum Well, P. Tripathi, S.T. Hasan, S.S.Z. Ashraf & A.C. Sharma, AIP conference proceedings (2014). [24] Effect on dynamic screening for determination of energy loss rate in disordered quantum well, P. Tripathi, S.T. Hasan and K.N. Vyas, AIP conference proceedings 1536, 137 (2013) [25] Dynamic Deformation Potential Electron Phonon Interaction in Disordered Quantum Well, P. Tripathi, S.S.Z. Ashraf, S.T. Hasan 1 & A.C. Sharma, AIP Conf Proceedings, 1447, 1055 (2012) [26] Dynamically screened Electron-Phonon Interaction in Disorder Semiconductors, P. Tripathi, S.S.Z. Ashraf, S.T. Hasan, K.N. Vyas and A.C. Sharma, AIP Conf Proc pp (ICACNM-2011) [27] Energy relaxation in two dimensional electron gas with dynamic deformation potential, P. Tripathi, S.T. Hasan K.N. Vyas and A.C. Sharma, Proceeding of Solid state Physics Symposium, 54, 927, (2009) [28] Dynamically screened electron-acoustic-phonon scattering in disordered semiconductor quantum wells. S.S.Z. Ashraf, S.K. Ambavale, P. Tripathi and A.C. Sharma, Proc. of the Solid state Physics symposium, 52, 825 (2007) [29] Energy exchange and dynamic screening on electron-electron scattering rate in two dimensional gas confined to GaAs heterostructure. P. Tripathi and A.C. Sharma, Proc. of the DAE solid state Physics symposium, 51, 781 (2006). [30] Energy exchange spectrum for electron-electron scattering in 2D, P. Tripathi and K.N. Vyas Proc. of the DAE solid state Physics symposium, 49, 269 (2004). [31] Energy Exchange rate via Electron Electron Collision in GaN heterostructures, P. Tripathi and B.K. Ridley, Proc. of the Solid State Physics Symp. 46, 655 (2003). [32] Electron Relaxation Time in Type-II Superlattices, P. Tripathi and A.C. Sharma, Proc. of the Solid State Physics Symp. 42, 651 (1999) [33] Electron-Electron and Electron-Impurity Scattering and their Effects on the Properties of Semiconductor superlattices, P. Tripathi, Proc. of the Solid State Physics Symp. 42, 111 (1999).

10 [34] Electron-Electron Scattering in Semiconductor Superlattices, P. Tripathi and A.C. Sharma, Proc. of the Solid State Physics Symp. 41, 276 (1998). [35] Damping of Plasmons in a Doped Semiconductor superlattice, P. Tripathi and A.C. Sharma, Proc. of the Solid State Physics Symp. India, 40C, 166 (1997). [36] Transverse Plasmons in Layered Electron Gas, A.C. Sharma, S.P. Apell and P. Tripathi, Proc. of the Solid State Physics Symp. India, 38C, 408 (1995). [37] Plasmons in Strained semiconductor superlattices, P. Tripathi and A.C. Sharma, Proc. of the Solid State Physics Symp. India, 37C, 137 (1994). CONFERENCE/WORKSHOP ATTENDED: A- International Conferences 1. Second International Conference on Material Science, th February, 2017, organisied by Department of Physics, Tripura Agartala, India. 2. Fourth International Conference on Nanostructured Materials and Nanocomposites (ICNM 2017), organisied by IIUCNN Mahatma Gandhi Kottayam, Kerala, India, during February, Advanced material World Congress, 2015, oraginised by Viking Line Cruise M/S Mariella, Stockholm, Sweden from 23 rd -26 th August, International conference on Aligarh- Nano-IV, Organized by Applied Physics department, ZHCET, AMU, Aligarh, during March 15-16, Second International Conference on Nanostructured Materials and Nanocomposites (ICNM-2014), Oragnized by International and Inter University Centre for Nanoscience and Nanotechnology (IIUCNN) Mahatma Gandhi Kottayam. Kerala, India. 6. International conference of advanced on Nanoscience and Nanotechnology, organized by Punjab Chandigarh during 22 Feb. -25 Feb International workshop on Hyperfine structure organised by Physics Department, Faculty of Science, M.S. from Feb.11-14, th International conference of Physics of Semiconductor, Orginised by Institute of Physics at Edinburgh (U.K. ) from July 29-Aug 2, The 5 th IUMRS International Conference in Asia, at Indian Institution of Science, Bangalore, India from Oct , 1998.

11 B- National Conference 1. Solid State Physics Symposium, Organised by DAE at IACS, Jadavpur Calcutta, from Dec. 27 to Dec Course on Computational Physics conducted by IPA, Bombay chapter at BARC, Mumbai, from Feb , National Symposium on Physics of Solids and Solid State Devices, Organised by Jai Narayan Vyas Jodhpur, from Nov , National Symposium on Physics of Semiconductor Nanostructures, Organised by I.I. T., New Delhi, from Jan , Solid State Physics Symposium, Organised by DAE at Cochin University of Science & Technology, Kochi, Kerala from Dec , National Seminar on Recent Developments in Condensed Matter Physics, Organised by UGC, New Delhi at Govt. Autonomous Science College, Gwalior, from Sept , Solid State Physics Symposium, Organised by DAE at Kurukshetra Kurukshetra from Dec , One day Seminar on Industrial Application of Materials, Organised by Physics Department, M.S. on March 21, National Conference on Semiconductor Materials & Recent Technology ( SMART- 99) Organised by Department of Physics, G.B. Pant University of Agriculture & Technology, Pantnagar from Nov. 1-3, Solid State Physics Symposium, Organised by DAE at Indira Gandhi Centre for Atomic, Kalpakkam, Timilnadu, from Dec , th Gujarat Science Congress, Organised by Gujarat Science Academy and Faculty of Science, M.S. from Feb , National workshop on chemistry and Application of Radioisotopes (RCARI) organised by Department of Physics, faculty of Science M.S. University of, Vadodara , from 26 th -Oct.4 th, Solid State Physics Symposium, Organised by DAE at Jiwaji Gwalior, India from Dec , National conference on nanostructures, organised by Physics Department, Faculty of Science, M.S. in June Solid State Physics Symposium, Organised by DAE at G.N. Dev, Amritsar, India from Dec , rd Indian Science congress, Organised by N.G. Runga Agriculture Hyderabad, India from Jan.3-7, National Conference on Condensed Matter and Materials Physics (CMMP06), Organised by Physics Department, The M.S. University of, Vadodara, from Jan , Solid State Physics Symposium, Organised by DAE at Barkatullah Bhopal, India from Dec , 2006.

12 22. National conference on Physics of Nanostructure and Bio-molecules (NCPNB-07), organized by Physics Department, MS, from Jan Solid State Physics Symposium, Organised by DAE at MS University, Vadodara, India from Dec.14 th -18, National conference of Computational Physics, organized by MS University of, Vadodara, during 1-2 Feb National workshop on Aligarh- Nano-I, Organized by Applied Physics department, ZHCET, AMU, Aligarh during March th DAE-Solid State Physics symposium, Oraganised by DAE at SRM Kattanklulathur, Chennai during 19 th Dec. 23 Dec Regional science congress on science for shaping the future of India, Oragnised by The M.S. University of, during Sept , National workshop on Aligarh- Nano-II, Organized by Applied Physics department, ZHCET, AMU, Aligarh, during March 10-12, National workshop on Aligarh- Nano-III, Organized by Applied Physics department, ZHCET, AMU, Aligarh, during March 15-16, BRIEF SUMMARY OF WORK DONE I have been doing research in the field of condensed matter theory since last 14 years. My field of interest is condensed matter theory and more specific Low dimensional/nanostructure/synthesis and chaterisiation of Nanoparticles. My current research interests are lies on different properties of some metal oxide nanoparticles. My Ph.D. work, which I completed, deals, with facets of electron-electron interaction and electron impurity scattering and their effects on the properties of semiconductor superlattices. First, we calculated complex frequency as a function of wave vector for coupled electron-hole plasma oscillations in doped GaAs superlattice. It is found that complex frequency shows sudden change at critical wave-vector-value determined by intrinsic parameters of the superlattice. Above critical wave vector value, superlattice enters into a diffusive regime. Next we calculated frequencies of coupled plasmonphonon modes and the line shapes for the light scattering in In1-xGaxAs/GaSb1-yAsy, type- II compositional superlattice It is found that in homogeneity in the background of electron (hole) gas and the phase transition from semiconductor to semi-metal phase or vice-versa prominently affects plasma oscillation and their line shapes. Using Fermi- Golden rule, a calculation for electron-electron (hole-hole) and electron-hole (holeelectron) scattering processes in semiconductor superlattices is performed. We found that both small and large momentum transfer scattering processes for intralayer as well as interlayer interactions contribute to transport relaxation time at all values of temperature and single particle energy. My Post doctorate research deals with the Transport properties of Gallium Nitride and related structures. Within this topic we have studied detailed comparison between the hot-electron rates for energy and momentum relaxation in electron-acoustic-phonon scattering and energy and momentum exchange rates in electron-electron scattering in a

13 GaN heterostructure. In the case of piezoelectric scattering full account is taken of the anisotropy of the interaction and corresponding form factors has been calculated. The interaction with acoustic phonons is assumed to be statically screened. Dynamics screening of the electron-electron interaction is shown to give rise to resonances associated with plasmons-phonons coupled mode effects with overall dynamic rates rather insensitive to electron density at least for densities around 1x10 12 cm -2. At these densities electron-electron scattering easily dominates the energy and momentum distribution at energies below the optical-phonon energy and is comparable with the optical phonon contribution above the phonon energy. The condition for the formation of a drifted Maxwellian distribution is discussed. The properties of dynamically-screened electron-electron interactions in 2D and quasi-2d semiconductor are described analytically for the situation where the electron gas obeys classical statistics. The electron-electron interaction is taken to be screened by the polar lattice and by free electrons in the lowest sub band. The character of the screening is shown to be critically dependent on the energy and momentum exchanged in the electron-electron interaction. A remarkable feature is the resonant enhancement of the interaction strength by coupled-phonon-plasmon mode effects. As a consequence, the coupled-mode enhancement of the electron-electron energy exchange rate offers substantial competition to the energy-relaxation rate of electrons via optical-phonon emission. We studied the effect of dynamically screened deformation potential on the electron longitudinal phonon relaxation in disordered two dimensional electron gas. On the consideration of the dynamic dielectric function and polarization operator, frequency - dependence, we find a significant change in the temperature exponent as well as the prefactor from the earlier reported approximate temperature power law dependence T 4 obtained under static strong screening and impurity limit. More strikingly, a reversal in the character of the dependence of scattering rate on mean free path takes place on the incorporation of dynamic screening where the behavior changes from the static 1/l to 2 dynamic l at T 1.0K and l 10nm. The temperature and mean free path variations of depends strongly on disorder. The character of the electron phonon interaction via 1 e ph the deformation potential (DP) is affected significantly by the inclusion of the dynamic screened DP and dynamic polarization operator. On inclusion of the dynamic screened DP the temperature exponent is enhanced at lower temperatures and reduced at higher temperatures from that of the analytical T 4 result obtained under statically screened DP approximation. The magnitude is also reduced by utmost four orders of magnitude in the temperature range considered for l=0.3nm and the temperature dependency for this dynamic curve reads T More strikingly, a reversal in the character of the dependence of scattering on mean free path takes place on the incorporation of dynamic screened DP where the behaviour changes from the static 1/l to dynamic l 2 at T=1.0K and l=10nm. Hence, it can be concluded from our study that the dynamic nature of screened DP plays a prominent role and governs strongly the temperature and mean free path dependence of the electron phonon relaxation.

14 Further, We investigated the electron energy loss rate through the emission of acoustic phonons in disordered two dimensional electron gas in the deformation coupling limit. The energy loss rate has been determined by considering dynamic screening of electrons as various earlier studies have shown that static screening underestimates the energy loss rate. We find a change in the temperature exponent as well as the pre-factor β from the earlier reported approximate temperature power law dependence βt 6 obtained under static and dynamic strong screening and impurity limit. The difference in magnitude between the approximate analytic and numerical results mounts at decreasing sub-kelvin temperatures with the pre-factor being enhanced about three times at a temperature 100mK and mean free path length 8 nm, and the power dependency decreasing from the analytically derived T 6 to numerically observed T 5.2. The electron energy loss rate through the emission of acoustic phonons via deformation potential (DP) is significantly modified by the inclusion of dynamic DP. On comparison of the approximate analytical strong screening static and dynamic results with the complete numerical strong screening static and dynamic results, we observe that, (i) the analytical results and numerically computed static result coincide below a temperature of ~ 200mK, but the numerical dynamic result shows an enhanced energy loss rate than the rest of the three results for this limit of temperature with a difference seen in both magnitude as well as exponent value. The magnitude differs by about three times and the exponent varies as T 5.2 at mean free path 8nm and temperature 100mK, (ii) in the intermediate temperature range (200mK-600mK) all the four results lie in close proximity to each other, (iii) the analytic dynamic screening result reduces to analytic static screening result at temperatures in the range of 600mK to 5K, and the numerical dynamic screening result close in to numerical static result at temperatures in the said range, (iv)for this range of temperature, the trend in magnitude behavior reverses with the analytical curves lying above the numerical curves up to the plotted limit. So, this study concludes that the dynamic nature of screened DP cannot be ignored as it plays a noticeable role and governs the temperature and mean free path dependence of the electron energy relaxation. References: 1.. Prof. A.C. Sharma, Physics Department, Faculty of Science, The M.S India. Phone No. +91 (265) , Mobile No.: acs_phy@yahoo.com 2. Prof. B.K. Ridley (FRS) Department of E.S.E., University of Essex, Colchester CO4 3SQ UK bkr@essex.ac.uk Telephone No.:

15 3. Prof. P. K Jha Physics Department, Bhavnagar Bhavnagar, Gujarat prafullaj@yahoo.com Mobile No.: Prof. Alim Husain Naqvi Centre of Excellence Nanoscience and Nanomaterials, Department of Applied Physics, Faculty of Engineering and Technology, Aligarh Muslim Aligarh alimhnaqvi@yahoo.com Mobile No.: I hereby, undersigned, declare that all the information provided by me is true and fair. Pushpendra Tripathi Aligarh UP, India