<html><body><div style="font-family: times new roman, new york, times, serif; font-size: 12pt; color: #000000"><div><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b><span lang="EN-GB" style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;" data-mce-style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;"><img src="cid:e0ace69a309525e4336e0e9e8f11b87232cfd095@zimbra" data-mce-src="cid:e0ace69a309525e4336e0e9e8f11b87232cfd095@zimbra"><br></span></b></p><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b><span lang="EN-GB" style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;" data-mce-style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;"> </span></b></p><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b><span lang="EN-GB" style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;" data-mce-style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;">Institut za fiziku, Bijenička cesta 46,</span></b></p><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b><span lang="EN-GB" style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;" data-mce-style="font-family: 'Century Gothic','sans-serif'; color: #5f5f5f;">Velika predavaonica (I krilo IF-a)</span></b></p><b><span lang="EN-GB" style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;" data-mce-style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;"> petak, 20. prosinca 2013., u 10:00 sati</span></b></div><div><b><span lang="EN-GB" style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;" data-mce-style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;"> </span></b></div><div style="text-align: center;" data-mce-style="text-align: center;"><b><span lang="EN-GB" style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;" data-mce-style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;"><b><span style="font-size: 16.0pt; font-family: 'Times New Roman','serif'; color: #55913c;" data-mce-style="font-size: 16.0pt; font-family: 'Times New Roman','serif'; color: #55913c;">Correlation Effects and Itinerant Particles</span></b></span></b><b style="font-size: 12pt;"><span lang="EN-GB" style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;" data-mce-style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif'; color: #993300;"><b><span style="font-size: 16.0pt; font-family: 'Times New Roman','serif'; color: #55913c;" data-mce-style="font-size: 16.0pt; font-family: 'Times New Roman','serif'; color: #55913c;"> </span></b></span></b></div><div><br></div><div style="text-align: center;" data-mce-style="text-align: center;"><b><span style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif';">dr.sc. Neven Barišić</span></b></div><div style="text-align: center;" data-mce-style="text-align: center;"><b><span style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 14.0pt; font-family: 'Century Gothic','sans-serif';"> </span></b></div><div><p align="center" style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><b><i><span style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';">Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10,</span></i></b></p><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b><i><span style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';">1040 Vienna, Austria</span></i></b></p><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b><i><span style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';"> </span></i></b></p><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b> </b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">Understanding the nature of quasiparticles in the presence of strong correlations has been one of the</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">most challenging topics in physics. In this contribution, I will revisit several very different systems and</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">demonstrate that a key step in descriptions of their physical properties is related to the itinerant</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">quasiparticles and their interaction with localized degrees of freedom. Outstanding examples of such</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">systems are the high-temperature superconductors. Contrary to conventional wisdom, we find that</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">the in-plane resistivity in the pseudogap phase (1) of the model cuprate HgBa2CuO4+δ (2,3) exhibits</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">a quadratic temperature dependence of the resistivity (ρ</span></b><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';"> <b><span style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';">~</span></b> </span></b><b><i><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">T<b><i><sup><span style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';">2</span></sup></i></b></span></i></b><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">), the same behavior that is seen in</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">conventional Fermi liquids (4). This insight motivated collaborative optical conductivity measurements</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">that indeed yield the quadratic frequency dependence and temperature-frequency scaling expected </span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">for a correlated Fermi liquid (5). We arrive at the unexpected conclusion that, even close to the </span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">Mott-insulating state at zero doping, the cuprates behave like Fermi liquids.</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">By combining our dc resistivity results with published data for three structurally more complex cuprates,</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">we are able to obtain the universal sheet resistance throughout most of the temperature-doping phase</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">diagram (4). Current theoretical models can now be benchmarked against this universal result. Together </span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">with microwave results for <b><span style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';">HgBa <sub>2</sub> CuO <sub>4+δ</sub></span></b> and several other compounds (6, 7), we arrive at a revised phase </span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">diagram for the cuprates. </span></b><b style="font-size: 12pt;"><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">Finally, I will demonstrate that a combined analysis of the dc and optical conductivities in the</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">optimally-doped 122-iron pnictide also reveals a <i>T<b><i><sup><span style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 12.0pt; font-family: 'Century Gothic','sans-serif';">2</span></sup></i></b> </i>dependence of the normal state transport scattering rate </span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">(8, 9). Although the iron-pnictides are in many respects different from the cuprates, this</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">observation indicates that, quite generally, the superconductivity in “unconventional” superconductors</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">evolves from a conventional Fermi-liquid-like state.</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';"> </span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">1. Y. Li, V. Baledént, N. Barišić, Y. Cho, B. Fauque, Y. Sidis, G. Yu, X. Zhao, P. Bourges, M. Greven. Nature</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">455, 372 (2008).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">2. N. Barišić, Y. Li, X. Zhao, Y. Cho, G. Chabot-Couture, G. Yu, M. Greven. Phys. Rev. B 78, 054518 (2008).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">3. N. Barišić, S. Badoux, M. K. Chan, C. Dorow, W. Tabis, B. Vignolle, G. Yu, J. Béard, X. Zhao, C. Proust,</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">and Martin Greven. Nature Physics 9, 761 (2013).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">4. N. Barišić, Y. Li, G. Yu, X. Zhao, M. Dressel, A. Smontara, M. Greven. Proc. Natl. Acad. Sci. 110, 12235</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">(2013).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">5. S. I. Mirzaei, D. Stricker, J. N. Hancock, C. Berthod, A. Georges, E. van Heumen, M. K. Chan, X. Zhao, Y.Li, M. Greven, N. Barišić, D. van der Marel. Proc. Natl. Acad. Sci. 110, 5774 (2013).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">6. M. S. Grbić, N. Barišić, A. Dulčić, I. Kupčić, Y. Li, X. Zhao, G. Yu, M. Dressel, M. Greven, and M. Požek,</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">Phys. Rev. B 80, 094511 (2009).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">7. M. S. Grbić, M. Požek, D. Paar, V. Hinkov, M. Raichle, D. Haug, B. Keimer, N. Barišić, and A. Dulčić,</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">Phys. Rev. B 83, 144508 (2011).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">8. N. Barišić, D. Wu, M. Dressel, L. J. Li, G. H. Cao, and Z. A. Xu. Phys. Rev. B 82, 054518 (2010).</span></b></p><p style="text-align: justify; margin: 0px;" data-mce-style="text-align: justify; margin: 0px;"><b><span style="font-family: 'Century Gothic','sans-serif';" data-mce-style="font-family: 'Century Gothic','sans-serif';">9. D. Wu, N. Barišić, P. Kallina, A. Faridian, B. Gorshunov, N. Drichko, L. J. Li, X. Lin, G. H. Cao, Z. A. Xu, N.</span></b></p><p align="center" style="margin: 0px; text-align: left;" data-mce-style="margin: 0px; text-align: left;"><b><span style="font-size: medium;" data-mce-style="font-size: medium;"><b><span style="font-family: 'Century Gothic', sans-serif;" data-mce-style="font-family: 'Century Gothic', sans-serif;">L. Wang, and M. Dressel. Phys. Rev. B 81, R100512 (2010).</span></b></span><br></b></p><p align="center" style="margin: 0px; text-align: center;" data-mce-style="margin: 0px; text-align: center;"><b style="font-size: 12pt;" data-mce-style="font-size: 12pt;"><b><span lang="EN-GB" style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';"> </span></b></b></p><p align="center" style="margin: 0px; text-align: left;" data-mce-style="margin: 0px; text-align: left;"><b style="font-size: 12pt;" data-mce-style="font-size: 12pt;"><b><span lang="EN-GB" style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';"><br></span></b></b></p><p align="center" style="margin: 0px; text-align: left;" data-mce-style="margin: 0px; text-align: left;"><b style="font-size: 12pt;" data-mce-style="font-size: 12pt;"><b><span lang="EN-GB" style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';">Voditelji seminara IF-a: Nikša Krstulović i Osor Bari</span><span style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';" data-mce-style="font-size: 11.0pt; font-family: 'Century Gothic','sans-serif';">šić</span></b></b></p></div><div><br></div><div><br></div><div><span name="x"></span>*************************<br>Nikša Krstulović, PhD<br>Research associate<br><div><br></div>Institute of Physics<br>Bijenicka 46<br>HR-10000 Zagreb, Croatia<br><div><br></div>Phone: 00385 1 4698 872<br> 00385 1 4698 851<br>Fax: 00385 1 4698 889<br><div><br></div>http://www.ifs.hr/<br>http://spectra.ifs.hr/<br>**************************<br><div><br></div><span name="x"></span></div></div></body></html>