quantum spin liquid; chemical pressure; electron spin resonance; high pressure
Náfrádi Bálint, Náfrádi Gábor, Martin-Hamka Carole, Forró László, Horváth Endre (2017), Superior Water Sheeting Effect on Photocatalytic Titania Nanowire Coated Glass, in Langmuir
, 33(36), 9043-9049.
Szirmai P., Márkus B. G., Dóra B., Fábián G., Koltai J., Zólyomi V., Kürti J., Náfrádi B., Forró L., Pichler T., Simon F. (2017), Doped carbon nanotubes as a model system of biased graphene, in Physical Review B
, 96(7), 075133-075133.
Szirmai Péter, Náfrádi Bálint, Arakcheeva Alla, Szilágyi Edit, Gaál Richárd, Nemes Norbert M., Berdat Xavier, Spina Massimo, Bernard Laurent, Jaćimović Jaćim, Magrez Arnaud, Forró László, Horváth Endre (2017), Cyan titania nanowires: Spectroscopic study of the origin of the self-doping enhanced photocatalytic activity, in Catalysis Today
, 284, 52-58.
Szirmai Peter, Stevens Jeremy, Horvath Endre, Ciric Luka, Kollar Marton, Forro Laszlo, Nafradi Balint (2017), Competitive ion-exchange of manganese and gadolinium in titanate nanotubes, in CATALYSIS TODAY
, 284, 146-152.
Náfrádi B., Antal Á., Fehér T., Kiss L. F., Mézière C., Batail P., Forró L., Jánossy A. (2016), Frustration-induced one-dimensionality in the isosceles triangular antiferromagnetic lattice of δ -(EDT-TTF- CONMe2)2AsF6, in Physical Review B
, 94(17), 174413-174413.
Markus Bence G., Szolnoki Lenard, Ivan David, Dora Balazs, Szirmai Peter, Nafradi Balint, Forro Laszlo, Simon Ferenc (2016), Anisotropic Elliott-Yafet theory and application to KC8 potassium intercalated graphite, in PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
, 253(12), 2505-2508.
Nafradi B., Szirmai P., Spina M., Lee H., Yazyev O. V., Arakcheeva A., Chernyshov D., Gibert M., Forro L., Horvath E. (2016), Optically switched magnetism in photovoltaic perovskite CH3NH3(Mn:Pb)I-3, in NATURE COMMUNICATIONS
, 7, 13406.
Nafradi Balint, Choucair Mohammad, Dinse Klaus-Peter, Forro Laszlo (2016), Room temperature manipulation of long lifetime spins in metallic-like carbon nanospheres, in NATURE COMMUNICATIONS
, 7, 12232.
Spina M., Nafradi B., Tohati H. M., Kamaras K., Bonvin E., Gaal R., Forro L., Horvath E. (2016), Ultrasensitive 1D field-effect phototransistors: CH3NH3PbI3 nanowire sensitized individual carbon nanotubes, in NANOSCALE
, 8(9), 4888-4893.
Nafradi Balint, Nafradi Gabor, Forro Laszlo, Horvath Endre (2015), Methylammonium Lead Iodide for Efficient X-ray Energy Conversion, in JOURNAL OF PHYSICAL CHEMISTRY C
, 119(45), 25204-25208.
Strong correlations between electrons in metals can lead to ordered states like anti-ferromagnetic insulator or superconductor. On the other hand in some cases correlations may destroy the long-range order resulting in another novel state of matter like the non-Fermi-liquid or the long-sought spin liquid state. The study of the spin liquid state in low-dimensional organic compounds is the central theme of the present proposal. This will be the continuation and extension of our ongoing work on low-dimensional organic magnets and conductors.Spin liquids emerge from strong quantum fluctuations at low temperatures and are further enhanced by the low-dimensionality. They are predicted to exist in two dimensions as well [Anderson1973], however good physical realizations are rare. Recently, two family of organic charge transfer salts, kappa-(BEDT-TTF)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2 [Shimizu2003, Itou2008] were identified using various experimental techniques as having spin liquid ground state. However, the experimental findings and the attribution of the driving force for the spin liquid state are controversial. Theoretical descriptions evoke two competing, fundamentally distinct models. One is based on a half-filled Mott insulator where a delicate interplay of correlation effects and geometrical frustration drive the system into a spin liquid state. The other one describes the system as a quarter filled band material, where electronic fluctuations between adjacent molecules strongly couple to the spin degrees of freedom and account for the suppression of the magnetic order. However, none of these models include the Dzyaloshinsky-Moriya (DM) interaction which might be an important ingredient.Here we propose Electron Spin Resonance (ESR) spectroscopy studies of these organic spin liquid materials. ESR is an extremely sensitive local probe for both magnetic correlations and anisotropies. Contrasting ESR results on kappa-(BEDT-TTF)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2 will clarify the importance of band filling, electric dipole fluctuations and geometrical frustration effects. Furthermore, since DM interaction is absent in EtMe3Sb[Pd(dmit)2]2 while allowed by symmetry in kappa-(BEDT-TTF)2Cu2(CN)3 our ESR results will help to identify the importance of such an anisotropy.One of the theories stresses the importance of charge fluctuations. Complementing these studies, we will also investigate a unique molecular-conductor molecular-rotor hybrid material, (EDT-TTF-CONH2)2(BABCO). Here an accurate control of the electric dipole fluctuations coupled to the spin degrees of freedom can be studied.