Estudo da criticalidade quântica no sistema de onda de densidade de carga Lu(Pt1−xPdx)2In

Abstract

Quantum phase transitions have been intensively studied in condensed matter physics. Over the recent years, many systems were shown to present an ordered state that can be suppressed by external parameters leading to a quantum critical point (QCP). Investigations on systems with charge ordered QCP’s are, however, still scarce. In this work we study the 3D charge density wave (CDW)/superconducting material Lu(Pt1-xPdx)2In. This compound has a quantum critical point close to xc ~ 0:58 of Pd content, where the CDW state vanishes and superconductivity is enhanced (GRUNER et al., 2017). In this work we describe the synthesis process and the primary physical properties characterization such as electrical resistivity and heat capacity measurements of three compounds with Pd concentrations approaching the critical value xc (x=0.3,0.4,0.5). The compounds were growth by using an arc-melting furnace and using synchrotron x-ray powder diffraction we investigate the CDW superlattice peak as function of temperature and Pd content. We observe the presence of quantum fluctuations effects over the classical CDW phase transition by mapping the charge order parameter critical exponent (b) near the QCP. The critical exponent starts at value expected for 3-dimensional materials and monotonically grows and approaches the value predicted by mean-field theory near the QCP. This might be related with a dimensional crossover that occur due to the competition between the energy scales of quantum and classical fluctuations at relatively high temperatures, indicating the presence of a quantum critical point.