Measurement of chirality of charge-density-waves in TiSe 2 by using STM

Abstract

We report the chirality of charge density waves (CDW) in 1T-TiSe 2 by using scanning tunneling microscopy (STM) measurements. We found that the CDW intensity becomes Ia 1 : Ia 2 : Ia 3 = 1 : 0.7 ± 0.1 : 0.5 ± 0.1 , where Ia i ( i = 1 , 2, 3) is the amplitude of the tunneling current contributed by the CDWs. We found two states, in which the three intensity peaks of the CDW decrease clockwise and anticlockwise when we index each nesting vector in order of intensity in the Fourier transformation of the STM images. We found that this difference arises from CDW stacking along the c-axis at intervals of 2 c 0 / 3 . This chirality is attributed to the helical stacking such as cholesteric liquid crystals.