Sunday, April 6, 2014

Interview with Dr. Chetan Dhital

In our effort to highlight Nepali physicists, we are inviting recent physics-PhD graduates. We congratulate Dr. Chetan Dhital for defending his PhD in Physics. Presenting a brief interview with him.

First of all, thank you Nabin jee for your time and effort.
Q. Please tell us about yourself. (Nepal School, Masters experience and travel to PhD institutions. Did you teach? Also any links, personal websites, and a photo etc.)
I was born in Bahundangi, a remote village in Jhapa, Nepal. I passed SLC from a government school near my village. When I passed SLC, my goal was to become a B.Sc. teacher so I joined I. Sc. in MMAM Campus Biratnagar where I finished both I. Sc. and B.Sc. After finishing B.Sc., I taught in a boarding high school for about 1 year. During that one year I changed my mind and went to Kathmandu to study M. Sc. in physics. I started to realize the beauty and importance of physics during those four years of my Master study. After finishing M.Sc, I taught undergraduate physics courses in Damak Multiple Campus Damak, Jhapa Nepal for about 3 years. In 2008, I got the opportunity to come to Boston College for pursuing Ph.D. in physics.
Q. Could you please describe your PhD research in plain English.  
My work during Ph.D is more about the fundamental physics which may not have direct immediate application. I worked mainly on two systems (1) Oxides of Iridium (2) Iron based superconductors. My work is focused in understanding different exotic electronic/magnetic phases in these materials by measuring electrical transport, magnetization and neutron scattering techniques.
Wait: why exotic?
In a hand waving argument, if one tries to confine charged particles in a small volume then charges experience mutual electric repulsion which blocks their movement resulting in an insulator so called Mott insulator. If the charges are allowed to stay inside a larger volume, they can avoid strong repulsion and may result in conducting states if the volume (band) is half filled. This is main theme of conventional band theory. In a solid the charged particles are electrons and the volume is the orbital occupied by electrons. If we believe the above picture and take the particular examples of Sr3Ru2O7 and Sr3Ir2O7, we should expect more metallic behavior in Sr3Ir2O7 than that in Sr3Ru2O7 because 5d orbitals of iridium are more extended than 4d orbitals of ruthenium. But the reality is opposite i.e Sr3Ir2O7 is insulator and Sr3Ru2O7 is a metal. In fact most of the oxides containing iridium in its 4+ valence state show such deviation from conventional wisdom. This is why they are exotic. Here the major player is spin-orbit interaction strength in iridates which is not just a perturbation term as in 3d compounds. Thus iridates (oxides of iridium) host many exotic quantum phases like spin liquid, quantum spin ice, Mott-insulators etc. We map out the electronic/magnetic phase behavior some typical doped and parent iridates. Regarding the second project, the key question in high temperature superconductivity is the mechanism responsible for superconductivity. In iron-based superconductors, the superconducting transition is always preceded by crystal and magnetic structural transition. My study is focused in understanding the structural and magnetic phase behavior of the electron doped superconducting system via neutron scattering.
Q. What are the social applications of your research/ short-term or long-term impact of your research to the society?
As I already mentioned, they may not have direct social impact. However, as we know transition metal oxides are also called functional materials, which have very good thermal and chemical stability allowing their use over a wide range of temperature and different chemical environments. In fact modern day electronics are based on transition metal oxide devices. The properties of these oxides are governed by the interplay of different competing energy scales. More players mean more ways of tuning the properties of these functional materials.
I think I do not have to say anything about the social/economic impact of high temperature superconductor (I wish we had room temperature superconductor) in this fast paced world where we are severely lacking our energy demand. But, to know the superconductivity better, one has to know ‘what was there at high temperature that becomes superconductor at low temperature’. My research is about “what was at high temperature”?
Q. How was your graduate school experience? (Specifically in terms of preparations towards your PhD, awards etc. Which skill(s) in particular you needed to sharpen, skills that you already had from previous institutions etc.)
In my view, the graduate study in USA is more student centered and practical. However, the courses we took in Master level especially the solid-state physics courses were very helpful. For my case, the graduate study period was satisfactory. I had the opportunity to perform several experiments in different national laboratories around the world. I think the productivity depends up on several factors such as your devotion and interest in the work, your relation with PhD advisor, your field of study etc.
In my case, there was a good combination of all these factors. I was awarded with GMAG student dissertation award from American Physical Society. This award is given every year for 2 or 3 graduate students working in magnetism who are going to graduate within September of that year. The student has to be a member of GMAG unit in APS and should be nominated by his advisor. There are some other awards that are also included in the following link. also authored/coauthored about 16 peer reviewed journals which can be found in the following link: you are working in Neutron scattering then there is a website for Neutron scattering society of America which provides information about awards and conferences.
Q. Please share few useful tips that you wish you were told when you applied for PhD.
To be honest, I was not fully aware of American style when I applied for graduate program. I used to write email to office secretary rather than professors or graduate advisor, which was a big mistake. Here, one can directly write to graduate advisor without any hesitation. Nowadays, the access to internet is easier than the time I applied, so one can easily find the departments that match with his research interest. Although our interest does not always work, however, I would suggest giving priority to those departments where your research interests match.  If you have two options, then money should not be the primary factor for decision-making. Furthermore, familiarize yourself with some common programs like matlab, origin, mathematica, igor etc before coming here. I think there should be a computational course at least in master level physics.
Q. Where do you want to be in the next 5 years? What are your hobbies, and spare time activities?
For the next step, I am joining as a postdoctoral research associate in Oak Ridge National Laboratory.  My next step is to give a shot for research faculty in suitable graduate schools (You miss 100% of the shots you don’t take,). If that doesn’t work, I want to stay in some suitable research and development department. However, I like to say “it is life”.
If you have kids then definition of spare time becomes vague. However, if I have time then I know how to watch basketball, soccer and cricket. I also enjoy watching comedy programs and movies and of course Nepal and world news.