Jasper van Wezel (SIMES Friday Seminar)

Date/Time
Date(s) - Mar 28 2014
11:00 AM - 12:00 PM

Location
Shasta Room, Bldg. 40, Room 361

Category(ies)


Chiral charge and orbital order

Jasper van Wezel

Bristol University, England


Helical arrangements of spins are common among magnetic materials. The first material to harbor a corkscrew pattern of charge density on the other hand, was discovered only relatively recently [1]. This difference can be directly attributed to the nature of the involved order parameters: whereas rotating a magnetic vector around a propagation vector trivially yields a helical pattern, the purely scalar charge density cannot straightforwardly support a chiral state.

Here, I will resolve the paradox of how chiral charge order could nonetheless be observed in the charge density wave material 1T-TiSe2, by identifying the microscopic mechanism underlying its formation. It is shown that the emergence of chirality necessarily involves the simultaneous formation of orbital order [2], and may in fact be expected to be a rather generic property of a broad class of charge ordered materials [3]. I will also point out how the chiral charge and orbital order can be observed using variety of experimental probes [4], and comment on its possible occurrence in different material classes [5,6].

References:

[1] J. Ishioka et al., Phys. Rev. Lett., 105, 176401 (2010).

[2] J. van Wezel, Europhys. Lett., 96, 67011 (2011).

[3] J. van Wezel, Phys. Rev. B, 85, 35131 (2012).

[4] J.P. Castellan et al., Phys. Rev. Lett. 110, 196404 (2013).

[5] H. Fukutome, Prog. Theor. Phys. 71, 1 (1984).

[6] P. Hosur et al., Phys. Rev. B 87, 115116 (2013).