G. Adhikary (Avtor), Tanusree Saha (Avtor), Primož Rebernik Ribič (Avtor), Matija Stupar (Avtor), Barbara Ressel (Avtor), Jurij Urbančič (Avtor), Giovanni De Ninno (Avtor), A. Thamizhavel (Avtor), Kalobaran Maiti (Avtor)

Povzetek

Quantum materials display exotic behaviours related to the interplay between temperature-driven phase transitions. Here, we study the electron dynamics in one such material, CaFe$_2$As$_2$, a parent Fe-based superconductor, employing time and angle-resolved photoemission spectroscopy. CaFe$_2$As$_2$ exhibits concomitant transition to spin density wave state and tetragonal to orthorhombic structure below 170 K. The Fermi surface of this material consists of three hole pockets ($\alpha$, $\beta$ and $\gamma$) around $\Gamma$-point and two electron pockets around $X$-point. The hole pockets have $d_{xy}$, $d_{yz}$ and $d_{zx}$ orbital symmetries. The $\beta$ band constituted by $d_{xz}$/$d_{yz}$ orbitals exhibit a gap across the magnetic phase transition. We discover that polarized pump pulses can induce excitations of electrons of a selected symmetry. More specifically, while $s$-polarized light (polarization vector perpendicular to the $xz$-plane) excites electrons corresponding to all the three hole bands, $p$-polarized light excites electrons essentially from ($\alpha$,$\beta$) bands which are responsible for magnetic order. Interestingly, within the magnetically ordered phase, the excitation due to the $p$-polarized pump pulses occur at a time scale of 50 fs, which is significantly faster than the excitation induced by $s$-polarized light ($\sim$ 200 fs). These results suggest that the relaxation of different ordered phases occurs at different time scales and this method can be used to achieve selective excitations to disentangle complexity in the study of quantum materials.

Ključne besede

electronic structure;pnictides;chalcogenides;time-resolved spectroscopy;

Podatki

Jezik: Angleški jezik
Leto izida:
Tipologija: 1.01 - Izvirni znanstveni članek
Organizacija: UNG - Univerza v Novi Gorici
UDK: 53
COBISS: 80409859 Povezava se bo odprla v novem oknu
ISSN: 0295-5075
Št. ogledov: 1162
Št. prenosov: 4
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Slovenski jezik
Sekundarne ključne besede: electronic structure;pnictides;chalcogenides;time-resolved spectroscopy;
URN: URN:SI:UNG
Strani: str. 1-6
Letnik: ǂVol. ǂ136
Zvezek: ǂno. ǂ1
Čas izdaje: 2021
DOI: 10.1209/0295-5075/ac2dc0
ID: 13500757