Sanjoy K. Mahatha: Evidence of out-of-plane metallic band dispersion in commensurate charge density wave of 1T-TaS2

posted 9 Aug 2017, 03:49 by Peter Boggild
Sanjoy K. Mahatha, Arlette S. Ngankeu, Kevin Guilloy, Marco Bianchi, Charlotte E. Sanders, Kai Rossnagel, Jill Miwa, and Philip Hofmann
Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark

The 1T polymorph of layered transition metal dichalcogenide compound TaS2 undergo phase transition towards low temperature with a periodic structural distortion where the electrons organize themselves in regular pattern which is widely known as charge density wave (CDW) [1]. The commensurate CDW phase of 1T-TaS2 has widely been treated as a quasi two-dimensional phenomenon that coexist with a Mott insulating state. However, recent theoretical calculations predicted the coexistence of CDW phase with a nearly one-dimensional metallic dispersion perpendicular to the crystal planes. In this presentation, I will show the angle-resolved photo emission spectroscopy results which confirms the existence of this metallic band [2]. The experimental band width of this metallic band is in excellent agreement with the predicted stacking order of CDW between the adjacent layers and its periodicity along c axis.
1. K. Rossnagel, J. Phys.: Condens. Matter 23, 213001 (2011).
2. Arlette S. Ngankeu, Kevin Guilloy, Sanjoy K. Mahatha, Marco Bianchi, Charlotte E. Sanders, Kai Rossnagel, Jill A. Miwa, and Philip Hofmann, arxiv1705.00455.

Sanjoy Kr.  Mahatha is currently a Postdoc of Department of Physics and Astronomy at the University of Aarhus. His primary interest lies in studying the growth and electronic structure of two-dimensional Dirac materials and transition metal dichalcogenides. He received his M.Sc. degree in Physics from The University of Burdwan (2006) and a Ph.D. in Experimental Physics (2013) from Calcutta University where he studied the electronic structure of two-dimensional materials and metal overlayers using angle-resolved photoemission. After finishing his Ph.D, he spent little more than 3 years as a postdoctoral researcher in ISM-CNR and in the Elettra Synchrotron, Trieste, Italy studying the electronic structure of silicene and multilayer Si film on Ag(111) and quantization effects in magnetic thin films. His awards include TRIL fellowship awarded by ICTP for carrying out post-doctoral research work at Elettra - Sincrotrone Trieste (2013), MRSI Young Scientist Award (2012) and Best Poster Award in “JSPS-DST Asian Academic Seminar 2010”.