Eur. Phys. J. E (2010) 33: 175-181
https://doi.org/10.1140/epje/i2010-10658-3

Regular Article

Nematic-smectic-A-smectic-C multicritical point: An alternative model

Department of Physics, Presidency College, 86/1 College Street, 700 073, Kolkata, India

^* e-mail: pkmukherje@yahoo.co.in

Received: 31 May 2010
Revised: 30 July 2010
Accepted: 15 September 2010
Published online: 9 October 2010

Abstract

A new Landau-type phenomenological free-energy function to describe the nematic-smectic-A transition, smectic-A-smectic-C transition and nematic-smectic-C transition is proposed. The influence of pressure on the these phase transitions is discussed by varying the coupling between various order parameters. The phase diagram of the thermodynamic parameters is studied and a possible nematic-smectic-A-smectic-C bicritical point is predicted. We present a detailed analysis of the different phases that can occur and analyze the question under which conditions a bicritical point is observed in the phase diagram. The obtained topology of the pressure-temperature phase diagram is consistent with experimental results.