Huseyin Gökcan (promotion date: 1 September 2006)

Hot electron and hole transport in the spin valve transistors

Promotion Date: 13 July 2006

What was your thesis about?

An alternative for electron devices are the spin electron devices, using the spin of the electron as well as its charge. The first spintronics spin valve transistor device that works in room temperature has been in existence since 1993, I am the fourth PhD on the subject. It was made, by the way, in the cleanroom of MESA+.

The spin of the electron is interacts with magnetism, and you can influence the spin, either into a spin up or a spin down.

What was your specific angle ?

I researched the hole transport, which was not done before. The earlier spin valve transistors only the electrons were studied, in my case I studied holes that also behave as (positive) current carriers. Again here I was not the first, there was somebody before me who studied the holes. But in my research we tried to understand the physics of the transport. You have to know this in order to built successful devices. I demonstrated that there is a spin dependent transport in the holes.

Why all the focus on the spin?

Spintronics started in 1988, and ever since we are trying to implement the spin property of the charge carriers – electron or hole – into electronics, because we have reached the limits of development in traditional electronic devices. We cannot go infinitely smaller, we need the new functionalities that the spin gives us.

There already spintronic devices on the market using another phenomenon in the spintronics area that is called magneto resistance. The magnetic heads in hard disks called GMR (Giant Magneto Resistance) heads are based on this principle.

But your research sounds very fundamental

It is, but we use an actual device to study the fundamental physical phenomena.

What did you like best about your research?

Actually in research the driving force for me is working with something entirely new. In this field I have done something new, and that is the exciting.

Did you like living in the Netherlands?

(Hesitatingly): Uh, I like the organized way of living. I like the rules and how people adhere to them, for instance in traffic. I don’t like the weather, but the air is fresh and that is something I do like. I was to busy to join the cultural life.

Where are you from?

I am from Turkey. First I was in the US as a PhD candidate, at the Brown University in New England. But the financial planning in the US is very different from here, you professor has to find resources and every year you just have to wait and see whether you get a salary or not. That was difficult, because I wanted to get married and besides, the US is very far from Turkey. So I switched to this institute, where the money for the project was allotted for all of the four years. There is a story attached to this: when I went to the Dutch Embassy in Boston to get the paperwork done, I first heard of the attacks on the Twin Tower in New York. I was a very tense period in the US, when I travelled to the Netherlands for instance half of the plane was empty.
But the tragedy of September 11^th more or less led to my new job. I had met the CEO of the company prior to this in the US. He had gone back to Turkey and called me asking to report on the events following the disaster as a favour.

What is it that you are going to do next?

Something completely different, even out of research. I am planning to return to Turkey but in research in government institutes the pay is very low. I have been working very hard over the last years and no longer like to live on such a small salary. So I will start in a management job in a media company. It is a very international company, with media all over the world. I will work in an operations’ research department planning the projects. My driving force has always been the development of new things. My new job certainly involves that.