Andrea Cavalleri

Abstract:

Time- and angle-resolved photoemission spectroscopy directly enables observation of electron dynamics in condensed matter. Using EUV high harmonic probe extends the observation window in energy and momentum. Tunable mid-infrared pumping allows control of excitation mechanisms.

Abstract:

We use femtosecond Resonant Soft X-ray Diffraction to observe heterogeneous melting of antiferromagnetic order in an epitaxially grown NdNiO3 film. Cross-interface coupling launches a propagating phase front following direct lattice excitation of the LaAlO3 substrate. © 2014 OSA.

Abstract:

Using EUV high harmonic probe in time- and angle-resolved photoemission spectroscopy extends the energy and momentum observation window for studies of electron dynamics in condensed matter, while tunable mid-infrared pumping allows control of excitation mechanisms. © 2014 OSA.

Abstract:

Nonlinear optical excitation of infrared active lattice vibrations has been shown to melt magnetic or orbital orders and to transform insulators into metals. In cuprates, this technique has been used to remove charge stripes and promote superconductivity, acting in a way opposite to static magnetic fields. Here, we show that excitation of large-amplitude apical oxygen distortions in the cuprate superconductor YBa2 Cu3 O6.5 promotes highly unconventional electronic properties. Below the superconducting transition temperature (Tc = 50 K) inter-bilayer coherence is transiently enhanced at the expense of intra-bilayer coupling. Strikingly, even above T c a qualitatively similar effect is observed up to room temperature, with transient inter-bilayer coherence emerging from the incoherent ground state and similar transfer of spectral weight from high to low frequency. These observations are compatible with previous reports of an inhomogeneous normal state that retains important properties of a superconductor, in which light may be melting competing orders or dynamically synchronizing the interlayer phase. The transient redistribution of coherence discussed here could lead to new strategies to enhance superconductivity in steady state. © 2014 Macmillan Publishers Limited. All rights reserved.

Abstract:

Time- and angle-resolved photoemission spectroscopy directly enables observation of electron dynamics in condensed matter. Using EUV high harmonic probe extends the observation window in energy and momentum. Tuneable mid-infrared pumping allows control of excitation mechanisms. © OSA 2014.