The electric pulse-induced responses of 1T-TaS2 and 1T-TaS1.6Se0.4 crystals in the commensurate charge-density-wave (CCDW) phase in the hysteresis temperature range have been investigated. We observed that abrupt multi-steps of the resistance are excited by electric pulses at a fixed temperature forming multi-metastable like states. We propose that the response of the system corresponds to the rearrangements of the textures of CCDW domains and the multi-resistance states or the nonvolatile resistance properties excited simply by electric pulses have profound significance for the exploration of solid-state devices.

The electric pulses induced responses of 1T-TaS 2 in the commensurate charge-density-wave phase in hysteresis temperature region (160∼210 K) have been investigated. We observed an abrupt jump of the resistance excited by pulse, followed by a slow relaxation process in a time scale of ∼100 s.At a fixed temperature, the various electric pulses can drive the system to multi meta-stable states.We propose that the spontaneous evolution or slow relaxation of the system by pulse excitations corresponds to the rearrangements of the textures of CCDW domains. 1The strongly correlated electronic materials are the interesting systems for condensed matter scientists, as the carriers couple together and thus novel physical properties appear 1 .The layered transition-metal dichalcogenides drive much attention in recent years, esp 1T-TaS 2 : the observed ultra-fast resistance switching 2,3 , the supercooled nearly commensurate charge-density-wave (CDW) phase at lower temperatures 4 , photosensitivity from visible to terahertz at room temperature 5 , and electrically driven reversible insulator-metal phase transition 4,6 . Though the microscopic mechanisms have not been disclosed until now, it is believed that the associated transport properties are attributed to the novel electron structures.1T-TaS 2 is one of the classical two-dimensional (2D) CDW systems. At room temperature, it reveals the nearly commensurate (NC) CDW. With decreasing temperature, a commensurate (C) CDW phase appears below 180 K whereas for heating process the CCDW state maintains up to 220 K, above which the NC phase establishes 7-9 . Scanning tunnelling microscopy has revealed that the NCCDW phase consists of trigonally packed CCDW domains separated by metallic regions that are not fully distorted 9 . As expected, the CCDW ground state is the starting point to understand the charge dynamics of the system 4,10-13 . Besides the observations of hidden states and supercooled states at lower temperatures, the region 160 ∼ 210 K is also interesting due to the remarkable hysteresis in dc transport properties, also known as the temperature region of metastability 14 . Photoemission spectroscopy, infrared conductivity and thermoelectric potential also exhibit hysteresis features [15][16][17] . Naively, understanding the properties in the hysteresis region would be inevitably related the CCDW and NCCDW phases.Because of the close proximity of the various competing charge ordered phases in energy, several external perturbations or excitations can effectively modulated the CCDW phase 2,4,18,19 , raising interesting questions about the dynamics near the phase transitions.Based on the accumulated results, the charge transport properties of 1T-TaS 2 are determined by sample dimensions, thermal history, photo excitation, electric field and pressure. These characteristics are believed to be supported by the intrinsic electrons and lattice structures, which range from microscopic processes of single carriers, through mesoscopic ordering of polarons, up to macroscopic frustra...

The electric field dependence of the dielectric properties and the non-linear conductance of 1T-TaS 2 below 50 K has been investigated. A large dielectric constant of about 10 4 is obtained up to 10 7 Hz, which can not be attributed to hopping of the localized carriers alone, the collective excitations of the commensurate charge-density-wave must be another contributor. The dielectric spectra disperse slightly in our measured temperature and frequency range. At a moderate dc bias

Calcium homeostasis is critical to amyloid beta precursor protein (APP) processing. Na(+)/Ca(2+) exchanger (NCX) proteins play an important role in maintaining intracellular Na(+) and Ca(2+) homeostasis in the brain under physiological and pathological conditions. We sequenced a hyper-variable region in intron 2 of the Na(+)/Ca(2+) exchanger 1 gene (NCX1), and investigated whether insertion/deletion variations in this region are associated with the occurrence for Alzheimer's disease (AD). Examining 413 AD patients and 361 healthy controls, we identified 3 insertion/deletion polymorphisms. No significant differences of the allele and genotype frequencies were observed between the AD cases and the controls for any of the three polymorphisms. However, among the AD patients whose age at onset (AAO) was 65 years or older (n = 299), carriers of a 14 bp insertion showed a lower average AAO (ins/ins and ins/del vs. del/del, 72.49 ± 5.17 vs. 74.28 ± 5.79, p = 0.016). It suggested that this 14 bp insertion/deletion polymorphism might modulate AAO in late-onset AD patients.

We investigated dependence of the dielectric properties on temperature and electric field below 50 K along the chain direction of o-TaS3. With external electric field increase, two threshold features could be identified. For electric fields somewhat larger than the lower threshold [Formula: see text], the dielectric constant starts to decrease whereas the conductivity increases due to the tunnelling of solitons. For higher external electric field we observe a saturation of dielectric response and analyze that the possible reasons may be related to the polarization behavior of charged solitons. With a decrease in temperature, the effect of external field on the dielectric response of the system weakens gradually and at 13 K it diminishes due to soliton freezing.