Search results for "Polarons"
showing 4 items of 4 documents
Frequency and temperature dependence of the electrical conductivity of KTaO3; Li and PbTiO3; La, Cu: Indication of a low temperature polaron mechanism
2008
Abstract Recently, the concept of polarons has again been at the focus of solid-state research, as it can constitute the basis for understanding the high-temperature superconductivity or the colossal magnetoresistance of materials. More than a decade ago there were some indications that polarons play an important role in explaining low temperature maxima in imaginary part of the dielectric constant e ″ ( T ) in ABO3 perovskites. In the present work we report the ac electrical conductivities of KTaO3; Li and PbTiO3; La, Cu and their frequency and temperature dependence. The real part of the complex ac conductivity was found to follow the universal dielectric response σ ′ ∝ ν s . A detailed t…
Orthogonality Catastrophe and Decoherence in a Trapped-Fermion Environment
2012
The Fermi edge singularity and the Anderson orthogonality catastrophe describe the universal physics which occurs when a Fermi sea is locally quenched by the sudden switching of a scattering potential, leading to a brutal disturbance of its ground state. We demonstrate that the effect can be seen in the controllable domain of ultracold trapped gases by providing an analytic description of the out-of-equilibrium response to an atomic impurity, both at zero and at finite temperature. Furthermore, we link the transient behavior of the gas to the decoherence of the impurity, and, in particular to the amount of non-markovianity of its dynamics.
Tunable Polarons in Bose-Einstein Condensates
2017
A toolbox for the quantum simulation of polarons in ultracold atoms is presented. Motivated by the impressive experimental advances in the area of ultracold atomic mixtures, we theoretically study the problem of ultracold atomic impurities immersed in a Bose-Einstein condensate mixture (BEC). The coupling between impurity and BEC gives rise to the formation of polarons whose mutual interaction can be effectively tuned using an external laser driving a quasi-resonant Raman transition between the BEC components. Our scheme allows one to change the effective interactions between polarons in different sites from attractive to zero. This is achieved by simply changing the intensity and the frequ…
Tuning the Photoresponse of Nano‐Heterojunction: Pressure‐Induced Inverse Photoconductance in Functionalized WO 3 Nanocuboids
2019
S.R. and S.S. contributed equally to this work. This work was mainly supported by the Natural Science Foundation of China (Grant No. 11874076), National Science Associated Funding (NSAF, Grant No. U1530402), and Science Challenging Program (Grant No. TZ2016001). D.E. thanks the financial support from Spanish MINECO under Grant No. MAT2016-75586-C4-1-P and from Generalitat Valenciana under Grant Prometeo/2018/123, EFIMAT. The X-ray diffraction measurements were performed at the BL15U1 station, Shanghai Synchrotron Radiation Facility (SSRF) in China. The HP XAS measurements were performed at 20 ID-C, APS, ANL. APS is supported by DOE-BES, under contract no. DE-AC02-06CH11357. The authors grat…