Optical conductivity in multiferroic GaV4 S8 and GeV4 S8: Phonons and electronic transitions
Închide
Conţinutul numărului revistei
Articolul precedent
Articolul urmator
712 0
SM ISO690:2012
RESCHKE, Stephan, MAYR, Franz, WANG, Zhe, LUNKENHEIMER, Peter, LI, Weiwu, SZALLER, David, BORDACS, Sandor, KEZSMARKI, Istvan, TSURKAN, Vladimir, LOIDL, Alois. Optical conductivity in multiferroic GaV4 S8 and GeV4 S8: Phonons and electronic transitions. In: Physical Review B, 2017, vol. 96, p. 0. ISSN 2469-9950. DOI: https://doi.org/10.1103/PhysRevB.96.144302
EXPORT metadate:
Google Scholar
Crossref
CERIF

DataCite
Dublin Core
Physical Review B
Volumul 96 / 2017 / ISSN 2469-9950 /ISSNe 2469-9969

Optical conductivity in multiferroic GaV4 S8 and GeV4 S8: Phonons and electronic transitions

DOI: https://doi.org/10.1103/PhysRevB.96.144302

Pag. 0-0

Reschke Stephan1, Mayr Franz1, Wang Zhe12, Lunkenheimer Peter1, Li Weiwu3, Szaller David45, Bordacs Sandor54, Kezsmarki Istvan45, Tsurkan Vladimir16, Loidl Alois1
 
1 University of Augsburg,
2 Helmholtz-Zentrum Dresden-Rossendorf,
3 Physikalisches Institut, Universität Stuttgart, Stuttgart,
4 Budapest University of Technology and Economics, Department of Physics, Budapest,
5 MTA-BME Lendület Magneto-optical Spectroscopy Research Group, Budapest,
6 Institute of Applied Physics, Academy of Sciences of Moldova
 
Disponibil în IBN: 5 februarie 2018


Rezumat

We report on optical spectroscopy on the lacunar spinels GaV4S8 and GeV4S8 in the spectral range from 100 to 23 000 cm-1 and for temperatures from 5 to 300 K. These multiferroic spinel systems reveal Jahn-Teller driven ferroelectricity and complex magnetic order at low temperatures. We study the infrared-active phonon modes and the low-lying electronic excitations in the cubic high-temperature phase, as well as in the orbitally and in the magnetically ordered low-temperature phases. We compare the phonon modes in these two compounds, which undergo different symmetry-lowering Jahn-Teller transitions into ferroelectric and orbitally ordered phases, and exhibit different magnetic ground states. We follow the splitting of the phonon modes at the structural phase transition and detect additional splittings at the onset of antiferromagnetic order in GeV4S8. We observe electronic transitions within the d-derived bands of the V4 clusters and document a significant influence of the structural and magnetic phase transitions on the narrow electronic band gaps.

Cuvinte-cheie
Mott Insulators, Ferroelectricity, multiferroics