ANOMALOUS TRANSPORT AND ELECTRONIC-PROPERTIES OF YB4AS3 UNDER HIGH-PRESSURE

Yb4As3 shows anomalous transport phenomena below the phase-transition temperature associated with an order-disorder transition due to the at omic arrangement between Yb3+ and Yb2+. Although the L-III spectrum sh ows no change in valence above and below the temperature, the large in crease of the trivalent component has been clearly observed with incre asing pressure. Comparing the pressure- and temperature-dependent resi stivity between Yb4As3 and Yb4Sb3, it is suggested that the anomalous transport properties of Yb4As3 are due to a characteristic electronic structure modulated with the phase transition.